Acetaldehyde in the Enders triple cascade reaction via acetaldehyde dimethyl acetal

• Alessandro Brusa,
• Debora Iapadre,
• Maria Edith Casacchia,
• Alessio Carioscia,
• Giuliana Giorgianni,
• Giandomenico Magagnano,
• Fabio Pesciaioli and
• Armando Carlone

Beilstein J. Org. Chem. 2023, 19, 1243–1250, doi:10.3762/bjoc.19.92

• because of its high reactivity. Herein, we report the Enders-type cascade reaction using acetaldehyde dimethyl acetal, as a masked form of acetaldehyde. This strategy directly converts acetaldehyde, nitroalkenes and enals into stereochemically dense cyclohexenals in good yield and excellent

• increasing structural and stereochemical complexity starting from readily available substrates. The scope of the process was shown to be successful with aliphatic aldehydes 2, aromatic nitroalkenes 3, and both aromatic and aliphatic unsaturated aldehydes 4. Given our recent interest in the use of a surrogate

• . Although the scope is limited to aromatic nitroalkenes and enals, the yields are good considering the complexity of the domino process that involves highly reactive partners, and the ees are consistently very high. Finally, albeit there is low diastereocontrol, the diastereomers can be easily separated by

Enolates ambushed – asymmetric tandem conjugate addition and subsequent enolate trapping with conventional and less traditional electrophiles

• Péter Kisszékelyi and
• Radovan Šebesta

Beilstein J. Org. Chem. 2023, 19, 593–634, doi:10.3762/bjoc.19.44

• the trapping of metal enolates by Michael reactions with nitroalkenes 122 and disulfonyl ethylenes 124 (Scheme 31) [67]. The conjugate additions of dialkylzinc, Grignard, and trialkylaluminum reagents to cyclic enones 121 were realized using previously established chiral phosphoramidite, carbene or

New advances in asymmetric organocatalysis

• Radovan Šebesta

Beilstein J. Org. Chem. 2022, 18, 240–242, doi:10.3762/bjoc.18.28

• possibilities in combination of covalent and noncovalent activation, our group designed and synthesized N-sulfinylpyrrolidine-containing ureas and thioureas and applied them in Michael additions of aldehydes to heterocycle containing nitroalkenes [25]. Dubey and Chowdhury showed that 1,4-conjugate additions of

Asymmetric organocatalytic Michael addition of cyclopentane-1,2-dione to alkylidene oxindole

• Estelle Silm,
• Ivar Järving and
• Tõnis Kanger

Beilstein J. Org. Chem. 2022, 18, 167–173, doi:10.3762/bjoc.18.18

• to synthesise indoloquinolizidines [5]. Moreover, six-membered and five-membered cyclic 1,3-diketones have been investigated in reactions with acetates of nitroalkenes [6], cyanoacrylates and benzylidene malononitriles [7], ortho-hydroxy-benzhydryl alcohols [8], α,β-unsaturated pyrazolamides [9] and

Solvent-free synthesis of enantioenriched β-silyl nitroalkanes under organocatalytic conditions

• Akhil K. Dubey and
• Raghunath Chowdhury

Beilstein J. Org. Chem. 2021, 17, 2642–2649, doi:10.3762/bjoc.17.177

• -nitrosilanes through a Cu(II)–chiral bipyridine complex catalyzed enantioselective silyl transfer reaction to nitroalkenes using Suginome’s silylboron reagent (Scheme 1a) [28]. Recently, we have reported the synthesis of chiral β-nitrosilanes via an organocatalytic conjugate addition of nitromethane to β

N-Sulfinylpyrrolidine-containing ureas and thioureas as bifunctional organocatalysts

• Viera Poláčková,
• Dominika Krištofíková,
• Boglárka Némethová,
• Renata Górová,
• Mária Mečiarová and
• Radovan Šebesta

Beilstein J. Org. Chem. 2021, 17, 2629–2641, doi:10.3762/bjoc.17.176

• Michael additions of aldehydes to nitroalkenes both under solvent-free conditions and in solution. The N-sulfinylurea catalyst was more efficient than the corresponding thiourea. For some substrates, enantioselectivities reached 98% ee. The stereogenic center on the sulfur did not have a considerable

• aldehydes and hydrogen-bond activation of nitroalkenes. Keywords: asymmetric organocatalysis; hydrogen bond; Michael addition; pyrrolidine; thiourea; urea; Introduction Asymmetric organocatalysis became one of the strategic ways for the efficient synthesis of chiral compounds [1]. Bifunctional catalysis

• -sulfinylurea as bifunctional organocatalyst [23]. The enantio- and diastereoselective addition of Meldrum’s acids to nitroalkenes via N-sulfinylurea catalysis gave products that were readily converted to pharmaceutically relevant compounds [24][25]. A sulfinylurea organocatalyst catalyzed a highly selective

Nitroalkene reduction in deep eutectic solvents promoted by BH₃NH₃

• Chiara Faverio,
• Monica Fiorenza Boselli,
• Patricia Camarero Gonzalez,
• Alessandra Puglisi and
• Maurizio Benaglia

Beilstein J. Org. Chem. 2021, 17, 1041–1047, doi:10.3762/bjoc.17.83

• nitroalkanes, valuable precursors of amines. A variety of nitrostyrenes and alkyl-substituted nitroalkenes, including α- and β-substituted nitroolefins, were chemoselectively reduced to the nitroalkanes, with an atom economy-oriented, simple and convenient experimental procedure. A reliable and easily

• ammonia borane in the chemoselective reduction of a variety of nitrostyrenes and alkyl-substituted nitroalkenes to the corresponding nitroalkanes, without any catalyst or additive [13]. We thought that the combination of an atom economic, very convenient and inexpensive reagent such as BH3NH3 in bio-based

• (entries 6 and 8, Table 1). Therefore, DES mixture B (ChCl/gly 1:2) and glycerol were selected as reaction media of choice to further investigate the reduction of nitroalkenes mediated by ammonia borane. Both solvent systems represent promising alternatives, green solvents for organic reactions; glycerol

Synthesis of imidazo[1,5-a]pyridines via cyclocondensation of 2-(aminomethyl)pyridines with electrophilically activated nitroalkanes

• Dmitrii A. Aksenov,
• Nikolai A. Arutiunov,
• Vladimir V. Maliuga,
• Alexander V. Aksenov and
• Michael Rubin

Beilstein J. Org. Chem. 2020, 16, 2903–2910, doi:10.3762/bjoc.16.239

• Within the last few years, we have developed and implemented a number of novel synthetic methodologies in our laboratories, involving acid-mediated cascade transformations of nitroalkenes and nitroalkanes, which target materials science and medicinal chemistry applications. It was demonstrated that upon

One-pot and metal-free synthesis of 3-arylated-4-nitrophenols via polyfunctionalized cyclohexanones from β-nitrostyrenes

• Haruyasu Asahara,
• Minami Hiraishi and
• Nagatoshi Nishiwaki

Beilstein J. Org. Chem. 2020, 16, 1830–1836, doi:10.3762/bjoc.16.150

• method toward the preparation of 3-arylated-4-nitrophenols. On the other hand, nitroalkenes possess an electron-deficient double bond, and hence, they serve as an excellent Michael acceptor and dienophile [12][13][14][15][16][17][18][19]. When β-nitrostyrene (1, Ar = Ph) is subjected to the Diels–Alder

• nitrophenol 5a. This protocol was also applicable to other nitroalkenes, 1b–f, to afford the corresponding 3-arylated-4-nitrophenols 5b–f. This reaction could be conducted in one pot without using any transition-metal reagent. Since the starting nitroalkenes were prepared by the condensation of a (hetero)aryl

• solid was recrystalized with a mixed solvent (hexane/dichloromethane 10:1) to afford nitrostyrene 1a [24] (1.99 g, 12.2 mmol, 76%) as yellow needles. The other nitroalkenes 1b–f [25][26][27][28][29] were prepared in the same way. One-pot Diels–Alder reaction of nitrostyrene 1a and Danishefsky’s diene (2

Synthesis of non-racemic 4-nitro-2-sulfonylbutan-1-ones via Ni(II)-catalyzed asymmetric Michael reaction of β-ketosulfones

• Alexander N. Reznikov,
• Anastasiya E. Sibiryakova,
• Marat R. Baimuratov,
• Eugene V. Golovin,
• Victor B. Rybakov and
• Yuri N. Klimochkin

Beilstein J. Org. Chem. 2019, 15, 1289–1297, doi:10.3762/bjoc.15.127

• nitroalkenes in the presence of Ni(II) complexes with various chiral vicinal diamines was studied. This reaction provides convenient access to non-racemic 4-nitro-2-sulfonylbutan-1-ones with two stereocenters with high yield and excellent enantioselectivity (up to 99%). It has been established that the

• ; Michael addition; nickel complexes; nitroalkenes; Introduction Sulfones are widely used in organic synthesis, particularly, in various reactions of C–C and C=C-bond formation [1][2][3][4]. The use of sulfones in Julia–Kocienski [1] and Ramberg–Bäcklund reactions [2] made this class of compounds

• reactions. Thus, ketonitrosulfones were obtained with good enantiomeric excesses via asymmetric addition of α-nitrosulfones to enones in the presence of organocatalysts [41]. Asymmetric addition of β-ketosulfones to nitroalkenes was implemented using various organocatalysts [42]. The reaction of

Assembly of fully substituted triazolochromenes via a novel multicomponent reaction or mechanochemical synthesis

• Robby Vroemans,
• Yenthel Verhaegen,
• My Tran Thi Dieu and
• Wim Dehaen

Beilstein J. Org. Chem. 2018, 14, 2689–2697, doi:10.3762/bjoc.14.246

• .14.246 Abstract A new metal-free one-pot three-component procedure towards fully substituted triazolochromenes has been developed, starting from commercially available materials. Salicylaldehydes and nitroalkenes were reacted under solvent-free conditions, followed by a 1,3-dipolar cycloaddition of the

• assembly of triazole-fused (hetero)cycles [24][33][34][35][36][37][38][39][40][41][42], we opted to develop a new one-pot two-step three-component reaction starting from salicylaldehydes, nitroalkenes and organic azides, without isolation of the intermediate 3-nitrochromenes, in a regioselective manner and

• study using various salicylaldehydes, nitroalkenes and organic azides. Solid salicylaldehydes gave diminished yields in the one-pot three-component protocol, hence a two-step mechanochemical approach was developed offering higher yields and resulting in a complementary route for solid salicylaldehydes

Asymmetric Michael addition reactions catalyzed by calix[4]thiourea cyclohexanediamine derivatives

• Zheng-Yi Li,
• Hong-Xiao Tong,
• Yuan Chen,
• Hong-Kui Su,
• Tangxin Xiao,
• Xiao-Qiang Sun and
• Leyong Wang

Beilstein J. Org. Chem. 2018, 14, 1901–1907, doi:10.3762/bjoc.14.164

• convenience and good stereoselectivity [5][6]. Accordingly, different versions of this reaction have been extensively studied. Notably, the Michael addition reaction of 1,3-dicarbonyl compounds to conjugated nitroalkenes is very important for the synthesis of chiral nitro carbonyl compounds, such as bioactive

• Michael addition reactions of acetylacetone and aromatic nitroalkenes. Results and Discussion Synthesis of catalysts The chemical structures and synthetic pathways for catalysts are shown in Scheme 1 and Scheme 2, respectively. A series of upper rim-functionalized calix[4]arene-based cyclohexanediamine

Recent applications of chiral calixarenes in asymmetric catalysis

• Mustafa Durmaz,
• Erkan Halay and
• Selahattin Bozkurt

Beilstein J. Org. Chem. 2018, 14, 1389–1412, doi:10.3762/bjoc.14.117

• 48 with nitroalkenes 49 (Scheme 13). The asymmetric Michael addition in the presence of 10–15 mol % of the macrocyclic catalysts 47a/47b afforded both enantiomers of the products 50 in high yields (up to 95%) and in high to excellent enantioselectivities (up to 99% ee). In order to confirm the role

• addition of 48 with 49 catalyzed by 47a and 47b. Enantioselective Michael addition of 51 to 52 catalyzed by calix[4]arene thioureas. Synthesis of calix[4]arene-based tertiary amine–thioureas 54–56. Asymmetric Michael addition of 34 and 57 to nitroalkenes 49 catalyzed by 54b. Synthesis of p-tert-butylcalix

Investigations towards the stereoselective organocatalyzed Michael addition of dimethyl malonate to a racemic nitroalkene: possible route to the 4-methylpregabalin core structure

• Denisa Vargová,
• Rastislav Baran and
• Radovan Šebesta

Beilstein J. Org. Chem. 2018, 14, 553–559, doi:10.3762/bjoc.14.42

• and pregabalin [9][10]. Later, hydrogen-bonding activation proved to be more general for obtaining Michael adducts via the addition of 1,3-dicarbonyl compounds to nitroalkenes. Chiral thioureas and squaramides, particularly those with the bifunctional mode of action, served as excellent catalysts in

• successful Michael additions to nitroalkenes in aqueous media [20][21], we have also tested the Michael addition of dimethyl malonate to nitroalkene 6 in brine. For this experiment, we have employed the more lipophilic organocatalyst C4, but the desired adduct 7 was formed only in small amount (14

CF₃SO₂X (X = Na, Cl) as reagents for trifluoromethylation, trifluoromethylsulfenyl-, -sulfinyl- and -sulfonylation and chlorination. Part 2: Use of CF₃SO₂Cl

• Hélène Chachignon,
• Hélène Guyon and
• Dominique Cahard

Beilstein J. Org. Chem. 2017, 13, 2800–2818, doi:10.3762/bjoc.13.273

• -nitroalkenes with trifluoromethanesulfonyl chloride [39]. They found out that in the presence of the photocatalyst Eosin Y, under visible-light irradiation, such substrates could be selectively converted into (E)-1-trifluoromethylalkenes in moderate to good yields (Scheme 30). A plausible mechanism for this

• -nitroalkenes because of the lower stability of the radical intermediate 38 generated. The variation of stability of this species also explained the higher yields obtained with β-nitrostyrene derivatives substituted by electron-withdrawing groups. Trifluoromethylation of alkynes: o-Azidoarylalkynes also proved

• trifluoromethylation of (hetero)arenes under photoredox catalysis. Direct C–H trifluoromethylation of five- and six-membered ring (hetero)arenes using heterogeneous catalysis. Trifluoromethylation of terminal olefins. Trifluoromethylation of enamides. (E)-Selective trifluoromethylation of β-nitroalkenes under

Conjugated nitrosoalkenes as Michael acceptors in carbon–carbon bond forming reactions: a review and perspective

• Yaroslav D. Boyko,
• Valentin S. Dorokhov,
• Alexey Yu. Sukhorukov and
• Sema L. Ioffe

Beilstein J. Org. Chem. 2017, 13, 2214–2234, doi:10.3762/bjoc.13.220

• particular focus on recent developments in this methodology and its use in total synthesis. Keywords: carbon–carbon bond formation; Michael addition; nitrosoalkenes; oximes; total synthesis; Introduction Conjugated nitrosoalkenes (NSA) are close analogs of α-nitroalkenes, which are important Michael

• acceptors in organic synthesis [1][2][3][4][5]. Unlike the parent α-nitroalkenes, α-nitrosoalkenes are unstable species usually generated in situ, and their synthetic potential has been studied in significantly less detail [6][7]. Because of relatively short lifetimes of α-nitrosoalkenes, conjugate addition

Synthesis of new pyrrolidine-based organocatalysts and study of their use in the asymmetric Michael addition of aldehydes to nitroolefins

• Alejandro Castán,
• Ramón Badorrey,
• José A. Gálvez and
• María D. Díaz-de-Villegas

Beilstein J. Org. Chem. 2017, 13, 612–619, doi:10.3762/bjoc.13.59

• hand, the presence of thiourea additives could activate nitroalkenes when used as substrates by double hydrogen bonding, which lead to improved reactivities [24]. Based on these findings, we decided to explore the effect of a Brønsted acid or an achiral thiourea as additive on the reaction between

Highly chemo-, enantio-, and diastereoselective [4 + 2] cycloaddition of 5H-thiazol-4-ones with N-itaconimides

• Shuai Qiu,
• Choon-Hong Tan and
• Zhiyong Jiang

Beilstein J. Org. Chem. 2016, 12, 2293–2297, doi:10.3762/bjoc.12.222

• class of sulfur-containing pro-nucleophiles in a highly enantio- and diastereoselective conjugate addition to nitroalkenes, providing α,α-disubstituted α-mercapto carboxylic acids [5]. Since then, several asymmetric variants using 5H-thiazol-4-ones as nucleophiles have been disclosed; such as amination

• activated alkenes, including nitroalkenes, 4-oxo-4-arylbutenones, 4-oxo-4-arylbutenoates and methyleneindolinones [10]. This work elucidated the feasibility of the electrophilic addition to the C2 position of 5H-thiazol-4-ones. More importantly, it provided a direct and convenient approach to synthesize

• chemoselectivity and thus the moderate yield. When the H-bond donor was changed from thiourea to urea (catalyst II), it did not provide better results (Table 1, entry 2) [17][19]. In the [4 + 2] annulation of 5H-thiazol-4-ones with nitroalkenes, dipeptide-based thiourea−amide−tertiary amine III (DP-TAA) was

Conjugate addition–enantioselective protonation reactions

• James P. Phelan and
• Jonathan A. Ellman

Beilstein J. Org. Chem. 2016, 12, 1203–1228, doi:10.3762/bjoc.12.116

• nitroalkenes Organocatalysts In the first reported example of the enantioselective protonation of a nitronate, Ellman and co-workers demonstrated that an N-sulfinylurea organocatalyst could be used to catalyze the addition of α-substituted Meldrum’s acids to terminally unsubstituted nitroalkenes (Scheme 37

• , including alkyl, phenethyl, pendant esters and thioethers, and an α-acetyloxy group (81–98% yield, 95.5:4.5 to 97:3 er). Slightly lower enantioselectivity was observed only when R1 was benzyl (93.5:6.5 er). Methyl, ethyl, n-butyl, and isopentyl R2 substituted nitroalkenes were efficient substrates (84–98

• % yield, 95.5:4.5 to 97:3 er). The resulting nitroalkane adduct 159 could be reduced and cyclized to access α,γ-disubstituted γ-lactams. Ellman and co-workers, in the second example of conjugate addition–enantioselective protonation with nitroalkenes, showed that thioacids 160 could be added in high

1H-Imidazol-4(5H)-ones and thiazol-4(5H)-ones as emerging pronucleophiles in asymmetric catalysis

• Antonia Mielgo and
• Claudio Palomo

Beilstein J. Org. Chem. 2016, 12, 918–936, doi:10.3762/bjoc.12.90

• the pionnering work by Trost in 2004 [26], several examples of the utility of the structurally related oxazol-4(5H)-ones (Figure 1b, X = O) have also been published, which involve mainly Michael additions (to enones [27][28], nitroalkenes [29][30], alkynones [31][32][33] and vinyl sulfones [34]), γ

• )-ones 1 as pronucleophiles in organocatalyzed Michael addition reactions 2-Thio-1H-imidazol-4(5H)-ones 1 (R = SBn) have been reported to be effective equivalents of N-subtituted (alkyl, aryl, allyl) α-amino acids in conjugate addition reactions to both, nitroalkenes and α-silyloxy enones as Michael

• acceptors in reactions promoted by bifunctional Brønsted bases. 1.2.1 Nitroalkenes as acceptors. Investigation of the base-catalyzed Michael addition reaction of 2-thio-1H-imidazol-4(5H)-ones 4 to nitroalkenes 5 [55] revealed that cinchona alkaloids such as quinine, (DHQ)2Pyr or even thiourea tertiary amine

Stereoselective amine-thiourea-catalysed sulfa-Michael/nitroaldol cascade approach to 3,4,5-substituted tetrahydrothiophenes bearing a quaternary stereocenter

• Sara Meninno,
• Chiara Volpe,
• Giorgio Della Sala,
• Amedeo Capobianco and
• Alessandra Lattanzi

Beilstein J. Org. Chem. 2016, 12, 643–647, doi:10.3762/bjoc.12.63

• nitroalkenes and commercially available 1,4-dithiane-2,5-diol to 3,4,5-substituted tetrahydrothiophenes, bearing a quaternary stereocenter, is presented. A secondary amine thiourea derived from (R,R)-1,2-diphenylethylamine was found to be the most effective catalyst when using trans-β-methyl-β-nitrostyrenes

• the bifunctional organocatalyst structure and reaction conditions will be required for further improvements of the challenging cascade process. Organocatalysts screened in the cascade reaction. Synthesis of catalyst VIII. Asymmetric sulfa-Michael/nitroaldol reaction of nitroalkenes 1–3 with 1,4

• -dithiane-2,5-diol (4) catalyzed by catalysts I–VIII. Solvent screening in the asymmetric Michael/nitroaldol reaction of 2a with 1,4-dithiane-2,5-diol (4) catalysed by amine thiourea VII. Asymmetric sulfa-Michael/nitroaldol reaction of nitroalkenes 2 with 1,4-dithiane-2,5-diol (4) catalysed by amine

The aminoindanol core as a key scaffold in bifunctional organocatalysts

• Isaac G. Sonsona,
• Eugenia Marqués-López and
• Raquel P. Herrera

Beilstein J. Org. Chem. 2016, 12, 505–523, doi:10.3762/bjoc.12.50

• derivative 4 to develop the first organocatalytic enantioselective Friedel–Crafts (F–C) alkylation of indoles, employing nitroalkenes as versatile electrophiles. In the presence of catalyst 4, the differently functionalized indole derivatives 2 reacted with aryl and alkyl nitroalkenes 3 in dichloromethane at

• of incorporating this scaffold into diverse organocatalysts. In 2008, Seidel’s group published a new example of an asymmetric addition of indoles to nitroalkenes, employing a novel catalyst design [24]. The authors envisioned that a protonated 2-pyridyl substituent could increase the acidity of the

• the compounds 32a–d, being S. Later, He and co-workers reported the use of several chiral multiple hydrogen-bond donating tertiary amine-based organocatalysts in the asymmetric addition of acetylacetone (36a) to the β-nitroalkenes 3. They found the thiourea 37 as a highly suitable catalytic structure

(Thio)urea-mediated synthesis of functionalized six-membered rings with multiple chiral centers

• Giorgos Koutoulogenis,
• Nikolaos Kaplaneris and
• Christoforos G. Kokotos

Beilstein J. Org. Chem. 2016, 12, 462–495, doi:10.3762/bjoc.12.48

• wide range of products in excellent yields (up to 95%) and selectivities (87–96% ee), confirming the generality of the protocol. In 2010, Zhong and co-workers demonstated that bifunctional thiourea 56 could catalyze the domino Michael–Henry reaction between nitroalkenes 82 and methyl 2,5

• , Enders and co-workers described the three-component domino Michael–Michael aldol reaction between β-ketoesters 153, nitroalkenes 77 and α,β-unsaturated aldehydes 154, producing heavily substituted cyclohexanes 155 containing six contiguous stereocenters with excellent stereocontrol (Scheme 49) [70]. In

• (Scheme 53). In 2008, Wang and co-workers described a very interesting Michael–Michael cascade of trans-3-(2-mercaptophenyl)-2-propenoic acid ethyl esters 167 and nitroalkenes 82 to produce thiochromane derivatives 168 catalyzed by the bifunctional thiourea 57 (Scheme 54) [75]. The reaction proceeded

Cupreines and cupreidines: an established class of bifunctional cinchona organocatalysts

• Laura A. Bryant,
• Rossana Fanelli and
• Alexander J. A. Cobb

Beilstein J. Org. Chem. 2016, 12, 429–443, doi:10.3762/bjoc.12.46

• vinylogous Michael addition reaction [48]. In this process, cyclic enones 52 are added to nitroalkenes 41 using dienamine catalysis (Scheme 13). Although no model is suggested with respect to how the 6’-OH is involved, it is clearly of importance as the analogous 6’-OMe derived cupreine catalyst gives

Organocatalytic and enantioselective Michael reaction between α-nitroesters and nitroalkenes. Syn/anti-selectivity control using catalysts with the same absolute backbone chirality

• Jose I. Martínez,
• Uxue Uria,
• Maria Muñiz,
• Efraím Reyes,
• Luisa Carrillo and
• Jose L. Vicario

Beilstein J. Org. Chem. 2015, 11, 2577–2583, doi:10.3762/bjoc.11.277

• nitroalkenes has been studied in the presence of two bifunctional catalysts both containing the same absolute chirality at the carbon backbone. The reaction performed in similar conditions allows us to control the syn or anti selectivity of the Michael adduct obtaining good yields and high enantiocontrol in

• all cases. Keywords: asymmetric diastereodivergent; enantioselective; Michael addition; nitroalkenes; nitroesters; organocatalysis; squaramides; Introduction The absolute stereochemistry of a molecule has a paramount influence on the properties that this compound will have when interacting with

• ][25][26]. In this context, we have recently reported a catalytic and enantioselective Michael/Michael cascade reaction in which α-nitro-δ-ketoesters react with nitroalkenes to provide densely functionalized cyclohexanes in excellent yield and stereoselectivity (Scheme 1) [27]. This reaction made use