(Bio)isosteres of ortho- and meta-substituted benzenes

• H. Erik Diepers and
• Johannes C. L. Walker

Beilstein J. Org. Chem. 2024, 20, 859–890, doi:10.3762/bjoc.20.78

• homologation and hydrolysis led to aldehyde (±)-46 which could then be oxidised to acid (±)-47 using a Pinnick oxidation. BCH 42b also led to ester (±)-48 via a Horner–Wadsworth–Emmons reaction followed by hydrogenation of the formed alkene. 1,2-BCH 44 could be turned into amine (±)-49 by oxime formation and

• cyclopropanation [44] (to (±)-66) of α-hydroxy silyl enol ethers (±)-65 followed by an acid-catalysed pinacol rearrangement to (±)-67. As exemplary derivatizations of 5-oxo-BCH (±)-67, 1,5-BCHs (±)-68, (±)-69 and (±)-70 were accessed by reductive amination, ketone reduction, and Horner–Wadsworth–Emmons olefination

Chemoenzymatic synthesis of macrocyclic peptides and polyketides via thioesterase-catalyzed macrocyclization

• Senze Qiao,
• Zhongyu Cheng and
• Fuzhuo Li

Beilstein J. Org. Chem. 2024, 20, 721–733, doi:10.3762/bjoc.20.66

• and phosphonate 48, were synthesized, employing Evans’ vinylogous aldol and Myers’ auxiliary-mediated alkylation reactions as key steps. By utilizing these two fragments, a Horner–Wadsworth–Emmons olefination, followed by thioester formation and desilylation, produced several different activated

• 59, which was reacted with phosphonate 60 through Horner–Wadsworth–Emmons (HWE) olefination. Afterward, the coupling of 61 and 62, followed by removing the silyl groups, gave the desired linear precursors 63. The investigation of the enzymatic macrocyclization suggested that CrpTE is able to accept a

Combretastatins D series and analogues: from isolation, synthetic challenges and biological activities

• Jorge de Lima Neto and
• Paulo Henrique Menezes

Beilstein J. Org. Chem. 2023, 19, 399–427, doi:10.3762/bjoc.19.31

• synthesis of combretastatin D-1 (1) using the flash vacuum pyrolysis (FVP) technique, which consisted on the contraction of 16-membered sulfone derivatives, by extrusion of sulfur dioxide [58]. The synthesis of the required sulfone was initiated by a Horner–Wadsworth–Emmons reaction between the aldehyde 52

Sequential hydrozirconation/Pd-catalyzed cross coupling of acyl chlorides towards conjugated (2E,4E)-dienones

• Benedikt Kolb,
• Daniela Silva dos Santos,
• Sanja Krause,
• Anna Zens and
• Sabine Laschat

Beilstein J. Org. Chem. 2023, 19, 176–185, doi:10.3762/bjoc.19.17

• condensation of enals 6 with aldehydes 7a or ketones 7b [6][7][8][9][10][11], isomerization of alkynones 8 [12][13][14][15], Horner–Wadsworth–Emmons reaction of unsaturated phosphonates 9 and aldehydes 10 [16][17], and dehydrogenation of enones 11 [18]. Further, Claisen rearrangement of vinyl propargylic

Identification and determination of the absolute configuration of amorph-4-en-10β-ol, a cadinol-type sesquiterpene from the scent glands of the African reed frog Hyperolius cinnamomeoventris

• Angelique Ladwig,
• Markus Kroll and
• Stefan Schulz

Beilstein J. Org. Chem. 2023, 19, 167–175, doi:10.3762/bjoc.19.16

• in a Michael addition with methyl acrylate, affording aldehyde 4 (Scheme 1). Instead of the original Wittig reaction [13], a Horner–Wadsworth–Emmons reaction using diethyl (2-methylallyl)phosphonate and BuLi led to a higher yield and formation of the pure (E)-isomer 5. The required phosphonate was

Catalytic aza-Nazarov cyclization reactions to access α-methylene-γ-lactam heterocycles

• Bilge Banu Yagci,
• Selin Ezgi Donmez,
• Onur Şahin and
• Yunus Emre Türkmen

Beilstein J. Org. Chem. 2023, 19, 66–77, doi:10.3762/bjoc.19.6

• starting from the commercially available triethyl phosphonoacetate (14, Scheme 2a). The deprotonation of 14 with NaH followed by alkylation using (iodomethyl)trimethylsilane afforded phosphonate 15 in 60% yield (7.0 g). Its subsequent Horner–Wadsworth–Emmons reaction with isovaleraldehyde resulted in the

Total synthesis of grayanane natural products

• Nicolas Fay,
• Rémi Blieck,
• Cyrille Kouklovsky and
• Aurélien de la Torre

Beilstein J. Org. Chem. 2022, 18, 1707–1719, doi:10.3762/bjoc.18.181

• group on C6 was introduced after cyclopropane ring-opening, ketone protection, epoxidation and reductive ring-opening of the resulting epoxide. A one-pot β-keto phosphonate formation/Horner–Wadsworth–Emmons reaction with formaldehyde afforded 38, a precursor for the key oxidative dearomatization-induced

Vicinal ketoesters – key intermediates in the total synthesis of natural products

• Marc Paul Beller and
• Ulrich Koert

Beilstein J. Org. Chem. 2022, 18, 1236–1248, doi:10.3762/bjoc.18.129

• ]. The α-ketoester 41 was accessible from amide 38, which in turn was obtained from allylic alcohol 37. Oxidation and Horner–Wadsworth–Emmons reaction with phosphonate 39 delivered the silyl enol ether 40, which was deprotected and cyclized via a Grubbs metathesis to α-ketoester 41. Subsequent

• was synthesized by a Horner–Wadsworth–Emmons reaction of phosphonate 48 with aldehyde 47. Enantiopure aldehyde 47 was easily accessible from oxazolidinone 46 via Evans-aldol chemistry [23]. Heating of the α-ketoester 49 led to the highly substituted cyclopentanol 50 in a good dr of ≈5:1 (minor

The stereochemical course of 2-methylisoborneol biosynthesis

• Binbin Gu,
• Anwei Hou and
• Jeroen S. Dickschat

Beilstein J. Org. Chem. 2022, 18, 818–824, doi:10.3762/bjoc.18.82

• . Results and Discussion Enantioselective synthesis of 2-methyllinalyl diphosphate The synthesis of (R)- and (S)-2-Me-LPP started with the Horner–Wadsworth–Emmons reaction [34][35] of sulcatone (2) with triethyl 2-phosphonopropionate to obtain ethyl 2-methylgeranate (3) as a mixture of the E and Z

Strategies for the synthesis of brevipolides

• Yudhi D. Kurniawan and
• A'liyatur Rosyidah

Beilstein J. Org. Chem. 2021, 17, 2399–2416, doi:10.3762/bjoc.17.157

• ) asymmetric dihydroxylation and epoxidation; 3) asymmetric hydrogenation; 4) Horner–Wadsworth–Emmons olefination; and 5) cyclopropanation, which are summarized in Table 4, including the overall yields and the number of steps required. This work is expected to provide useful information for researchers to

Fritsch–Buttenberg–Wiechell rearrangement of magnesium alkylidene carbenoids leading to the formation of alkynes

• Tsutomu Kimura,
• Koto Sekiguchi,
• Akane Ando and
• Aki Imafuji

Beilstein J. Org. Chem. 2021, 17, 1352–1359, doi:10.3762/bjoc.17.94

• –Wadsworth–Emmons (HWE) reaction of carbonyl compounds with organophosphorus reagents containing carbene sources and the 1,2-rearrangement of alkylidene carbenes and related species, referred to as Fritsch–Buttenberg–Wiechell (FBW) rearrangement [8][9]. While alkynes are synthesized from carbonyl compounds

• homologation [3]. Much effort has been devoted to developing a procedure for the synthesis of alkynes from carbonyl compounds, and the Corey–Fuchs method, the Seyferth–Gilbert method, and the Ohira–Bestmann modification have been developed (Scheme 1) [4][5][6][7]. These methods consist of the Wittig or Horner

A comprehensive review of flow chemistry techniques tailored to the flavours and fragrances industries

• Guido Gambacorta,
• James S. Sharley and
• Ian R. Baxendale

Beilstein J. Org. Chem. 2021, 17, 1181–1312, doi:10.3762/bjoc.17.90

Progress in the total synthesis of inthomycins

• Bidyut Kumar Senapati

Beilstein J. Org. Chem. 2021, 17, 58–82, doi:10.3762/bjoc.17.7

• )-diene 66 (E/Z = 19:1, separable) using the standard (E)-selective Horner–Wadsworth–Emmons (HWE) reaction. DIBAL-H reduction of ester 66 followed by MnO2 oxidation produced aldehyde (E,E)-67 stereoselectively. Unfortunately, attempted enantioselective aldol reactions of (E,E)-67 with silylketene acetal

All-carbon [3 + 2] cycloaddition in natural product synthesis

• Zhuo Wang and
• Junyang Liu

Beilstein J. Org. Chem. 2020, 16, 3015–3031, doi:10.3762/bjoc.16.251

• -ketophosphonate 89 in 86% yield (Scheme 6A) [41]. Hydrogenation of 89 followed by an intramolecular Horner–Wadsworth–Emmons olefination produced hexacyclic enone 90 in 91% yield over two steps. The conversion of enone 90 to longeracinphyllin A (10) was achieved in three steps. The syntheses of daphenylline (11

Synthetic approaches to bowl-shaped π-conjugated sumanene and its congeners

• Shakeel Alvi and
• Rashid Ali

Beilstein J. Org. Chem. 2020, 16, 2212–2259, doi:10.3762/bjoc.16.186

• further reaction with dienes furnished the DA-adducts 102a–d. In 2012, another type of functionalized sumanene, namely tris(ethoxycarbonylethenyl)sumanene 108 was prepared by Sakurai's group through ROM–RCM as well as Horner–Wadsworth–Emmons (HWE) reactions as key transformations (Scheme 26) [59]. To this

Syntheses of spliceostatins and thailanstatins: a review

• William A. Donaldson

Beilstein J. Org. Chem. 2020, 16, 1991–2006, doi:10.3762/bjoc.16.166

• silyl ether-protected 2-hydroxypropanals 15a and 15b via literature procedures [10], followed by the application of the Still–Gennari Z-selective Horner–Wadsworth–Emmons olefination [11]. Koide’s group [12][13] reported that the asymmetric addition of the enyne 16 to acetaldehyde in the presence of zinc

Facile synthesis of 7-alkyl-1,2,3,4-tetrahydro-1,8-naphthyridines as arginine mimetics using a Horner–Wadsworth–Emmons-based approach

• Rhys A. Lippa,
• John A. Murphy and
• Tim N. Barrett

Beilstein J. Org. Chem. 2020, 16, 1617–1626, doi:10.3762/bjoc.16.134

• inhibitors based on the tripeptide sequence Arg–Gly–Asp (RGD) are potential therapeutics for the treatment of idiopathic pulmonary fibrosis (IPF). Herein, we describe an expeditious three-step synthetic sequence of Horner–Wadsworth–Emmons olefination, diimide reduction, and global deprotection to synthesise

• cores for these compounds in high yields (63–83% over 3 steps) with no need for chromatography. Key to this transformation is the phosphoramidate protecting group, which is stable to metalation steps. Keywords: arginine; Horner–Wadsworth–Emmons; integrin; phosphoramidate; tetrahydronaphthyridine

• the Wittig step presented complications on both gram and kilogram scales. Herein, we report a novel synthetic sequence to tetrahydro-1,8-naphthyridines using a Horner–Wadsworth–Emmons reaction using diphosphorylated compound 7, proceeding in high yields and high purities without the need for

N-(1-Phenylethyl)aziridine-2-carboxylate esters in the synthesis of biologically relevant compounds

• Iwona E. Głowacka,
• Aleksandra Trocha,
• Andrzej E. Wróblewski and
• Dorota G. Piotrowska

Beilstein J. Org. Chem. 2019, 15, 1722–1757, doi:10.3762/bjoc.15.168

• peptidyl nucleosides with primarily antifungal properties. The stereoselective synthesis of (+)-polyoxamic acid ((2S,3S,4S)-144) was successfully carried out starting with Horner–Wadsworth–Emmons olefination of the aziridine aldehyde (2R,1'R)-6 which provided a 98:2 mixture of trans- and cis-acrylates 69b

Investigation of the electrophilic reactivity of the biologically active marine sesquiterpenoid onchidal and model compounds

• Melissa M. Cadelis and
• Brent R. Copp

Beilstein J. Org. Chem. 2018, 14, 2229–2235, doi:10.3762/bjoc.14.197

• –Wadsworth–Emmons (H.W.E.) reaction of n-hexanal with phosphonoester 19 [15] afforded an E/Z mixture of olefinic diesters, purification of which by silica gel column chromatography afforded a fraction of the desired E diester 20 (60%), a second fraction comprised of a 5:1 E/Z mixture and a third fraction of

• effort to reduce the complexity of the NMR spectra observed for the diastereomeric onchidal–pyrrole adducts, a range of simpler achiral n-pentyl 11–14 and cyclohexylmethyl 15–18 side-chained model compounds, as either the dialdehyde or masked dialdehyde variants, were prepared (Figure 2). Horner

A stereoselective and flexible synthesis to access both enantiomers of N-acetylgalactosamine and peracetylated N-acetylidosamine

• Bettina Riedl and
• Walther Schmid

Beilstein J. Org. Chem. 2018, 14, 856–860, doi:10.3762/bjoc.14.71

• of the four desired stereogenic centers. By extending compound 5 via a Horner–Wadsworth–Emmons (HWE) reaction [15] and subsequent stereoselective introduction of the corresponding nitrogen functionality, a route to four different 2-amino sugar stereoisomers has been elaborated. Results and Discussion

Volatiles from the tropical ascomycete Daldinia clavata (Hypoxylaceae, Xylariales)

• Tao Wang,
• Kathrin I. Mohr,
• Marc Stadler and
• Jeroen S. Dickschat

Beilstein J. Org. Chem. 2018, 14, 135–147, doi:10.3762/bjoc.14.9

• –Wadsworth–Emmons reaction with triethyl 2-phosphonopropionate (19) yielded ethyl (E)-2,4-dimethylhex-2-enoate (20) as a separable mixture of E and Z stereoisomers (E/Z = 10:1). The purified E diastereomer was reduced with DIBAl-H to the corresponding alcohol 21. A PCC oxidation and addition of

• (Figure 2A) that was similar to a data base spectrum of manicone ((E)-4,6-dimethyloct-4-en-3-one, 10), but no retention index for this compound was available from the literature. For unambiguous structural verification compound 10 was synthesised starting from 2-methylbutanal (18, Scheme 3). A Horner

The photodecarboxylative addition of carboxylates to phthalimides as a key-step in the synthesis of biologically active 3-arylmethylene-2,3-dihydro-1H-isoindolin-1-ones

• Ommid Anamimoghadam,
• Saira Mumtaz,
• Anke Nietsch,
• Gaetano Saya,
• Cherie A. Motti,
• Jun Wang,
• Peter C. Junk,
• Ashfaq Mahmood Qureshi and
• Michael Oelgemöller

Beilstein J. Org. Chem. 2017, 13, 2833–2841, doi:10.3762/bjoc.13.275

• and co-workers and incorporated an intramolecular Horner–Wadsworth–Emmons reaction as a crucial step [10]. Due to their diverse biological activities, a variety of synthetic pathways to 3-arylmethylene-2,3-dihydro-1H-isoindolin-1-ones has been developed over the past two decades [10][11][12][13][14

Recent progress in the racemic and enantioselective synthesis of monofluoroalkene-based dipeptide isosteres

• Myriam Drouin and
• Jean-François Paquin

Beilstein J. Org. Chem. 2017, 13, 2637–2658, doi:10.3762/bjoc.13.262

• interested in the Horner–Wadsworth–Emmons (HWE) olefination to develop the synthesis of α-fluoro-α,β-unsaturated ester 3, which can be used as a precursor for the synthesis of monofluoroalkene-based dipeptide isosteres [23]. Cbz-Gly-ψ[(Z)-CF=CH]-Gly 5 was obtained in seven steps (Scheme 1). First, triethyl 2

The chemistry and biology of mycolactones

• Matthias Gehringer and
• Karl-Heinz Altmann

Beilstein J. Org. Chem. 2017, 13, 1596–1660, doi:10.3762/bjoc.13.159

Base-promoted isomerization of CF₃-containing allylic alcohols to the corresponding saturated ketones under metal-free conditions

• Yoko Hamada,
• Tomoko Kawasaki-Takasuka and
• Takashi Yamazaki

Beilstein J. Org. Chem. 2017, 13, 1507–1512, doi:10.3762/bjoc.13.149

• trifluoroacetate at −80 °C, a Horner–Wadsworth–Emmons reagent [17] activated by LiBr and Et3N [18][19][20] was introduced to this solution at room temperature, leading to the formation of (E)-6 after the NaBH4 reduction of the resultant products (see Supporting Information File 1 for the detailed procedure). As