Enantioselective total synthesis of putative dihydrorosefuran, a monoterpene with an unique 2,5-dihydrofuran structure

• Irene Torres-García,
• Josefa L. López-Martínez,
• Rocío López-Domene,
• Manuel Muñoz-Dorado,
• Ignacio Rodríguez-García and
• Miriam Álvarez-Corral

Beilstein J. Org. Chem. 2022, 18, 1264–1269, doi:10.3762/bjoc.18.132

• -methylhepta-5,6-dienoate (3, 225 mg, 81%) isolated as light yellow oil. IR (ATR) ν (cm−1): 3434, 2972, 2928, 1958, 1723, 1436, 1374, 1172, 1028, 925, 853; 1H NMR (300 MHz, CDCl3) δ 4.77 (dq, J = 2.3, 3.2 Hz, 2H), 4.12 (q, J = 7.1 Hz, 2H), 4.05 (m, 1H), 2.42 (t, J = 7.2 Hz, 2H), 2.18 (s, 1H), 2.04–1.77 (m, 2H

• , 3H) ppm; 13C{1H} NMR (75 MHz, CDCl3, DEPT) δ 206.0 (C), 177.0 (C), 98.0 (C), 80.4 (CH), 77.5 (CH2), 28.5 (CH2), 26.1 (CH2), 15.0 (CH3) ppm; HRMS–ESI (Q-TOF, m/z): [M + H]+ calcd for C8H11O2,139.0759; found, 139.0782. Silver(I)-promoted cyclization of ethyl 4-hydroxy-5-methylhepta-5,6-dienoate (3) A

Coordination chemistry and photoswitching of dinuclear macrocyclic cadmium-, nickel-, and zinc complexes containing azobenzene carboxylato co-ligands

• Jennifer Klose,
• Tobias Severin,
• Peter Hahn,
• Alexander Jeremies,
• Jens Bergmann,
• Daniel Fuhrmann,
• Jan Griebel,
• Bernd Abel and
• Berthold Kersting

Beilstein J. Org. Chem. 2019, 15, 840–851, doi:10.3762/bjoc.15.81

• drastically alter its structural properties and reactivities. Prominent examples are the cis-bromination of α,β-unsaturated carboxylato ligands [2], regioselective Diels–Alder reactions of encapsulated dienoate ligands [3], and the stabilization of unusual co-ligand conformations, respectively [4]. The

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

Total syntheses of the archazolids: an emerging class of novel anticancer drugs

• Stephan Scheeff and
• Dirk Menche

Beilstein J. Org. Chem. 2017, 13, 1085–1098, doi:10.3762/bjoc.13.108

• to synthesize archazolid B (2) in only 19 steps from (S)-Roche ester 41 (longest linear sequence). O'Neil’s retrosynthetic analysis and strategy As discussed above one of the main difficulties of any archazolid synthesis involves the labile C1 to C5-dienoate system, which is prone to isomerization

Decarboxylative and dehydrative coupling of dienoic acids and pentadienyl alcohols to form 1,3,6,8-tetraenes

• Ghina’a I. Abu Deiab,
• Mohammed H. Al-Huniti,
• I. F. Dempsey Hyatt,
• Emma E. Nagy,
• Kristen E. Gettys,
• Sommayah S. Sayed,
• Christine M. Joliat,
• Paige E. Daniel,
• Rupa M. Vummalaneni,
• Andrew T. Morehead Jr,
• Andrew L. Sargent and
• Mitchell P. Croatt

Beilstein J. Org. Chem. 2017, 13, 384–392, doi:10.3762/bjoc.13.41

• this reaction, substitutions at every unique position of both coupling partners was examined and two potential mechanisms are presented. Keywords: decarboxylation; diene; dienoate; palladium; pentadienyl; tetraene; Introduction The construction of sp2–sp3 carbon–carbon bonds remains a difficult and

• carboxyl group [20][36][37][38][39]. Despite the absence of this type of reactivity, the decarboxylative coupling of a pentadienyl dienoate (9; Scheme 2) was desirable enough for our group’s synthesis of clinprost that we attempted the reaction [40][41]. Fortunately, this coupling reaction was successfully

• method described herein even more valuable. It was determined that modifying the dienoate motif yielded only the rearranged product under the reaction conditions, including the dihydro (14), cinnamate (15), benzoate (16), and acrylate (17) analogues (Scheme 2). Moreover, allylic dienoates 18 and 19 gave

Benzothiadiazole oligoene fatty acids: fluorescent dyes with large Stokes shifts

• Lukas J. Patalag and
• Daniel B. Werz

Beilstein J. Org. Chem. 2016, 12, 2739–2747, doi:10.3762/bjoc.12.270

• , 154.1, 156.7, 174.5; IR (ATR) (cm−1): 3031, 2994, 2919, 2851, 1703, 1469, 1415, 1310, 1287, 1257, 1219, 988, 897, 829, 747; HRMS (ESI) m/z: calcd for C19H24N2O2SNa+, 367.14507; found, 369.14518. Methyl (2E,4E)-5-(benzo[c][1,2,5]thiadiazol-4-yl)penta-2,4-dienoate (9): To a solution of conjugated

New metathesis catalyst bearing chromanyl moieties at the N-heterocyclic carbene ligand

• Agnieszka Hryniewicka,
• Szymon Suchodolski,
• Agnieszka Wojtkielewicz,
• Jacek W. Morzycki and
• Stanisław Witkowski

Beilstein J. Org. Chem. 2015, 11, 2795–2804, doi:10.3762/bjoc.11.300

• mixture formation. The reactions of ethyl sorbate and its 3-methyl substituted analogue (ethyl (2E,4Z/E)-3-methylhexa-2,4-dienoate) with various alkenes were chosen to examine the activity and selectivity profile of catalyst 9 (Table 4). The results clearly indicate that carbene 9 can promote the CM

• reactions of dienes with different olefins as efficiently as commercial Grubbs 2nd generation and Hoveyda–Grubbs 2nd generation complexes 1 and 2. Complex 9 catalysed the reactions of ethyl 3-methylhexa-2,4-dienoate in a completely selective manner taking into account product regio- and stereoselectivity

• , Table 4). Additionally, isomerised diene (ethyl (2E,4E)-3-methylhexa-2,4-dienoate, used in excess) was isolated from the reaction mixture. When ethyl sorbate was used, the formation of two CM products, A and B, was observed due to unselective metathetic scission of the C2–C3 and C4–C5 double bonds

Copper-catalyzed stereoselective conjugate addition of alkylboranes to alkynoates

• Takamichi Wakamatsu,
• Kazunori Nagao,
• Hirohisa Ohmiya and
• Masaya Sawamura

Beilstein J. Org. Chem. 2015, 11, 2444–2450, doi:10.3762/bjoc.11.265

• 3g reacted regioselectively to afford a conjugated 2,4-dienoate 4ag in 90% yield with excellent syn selectivity (Table 2, entry 11). Alkyl groups were also acceptable as β-substituent of the alkynoates (Table 2, entries 12–14). Alkynoate 3h with a methyl group at the β-position reacted with an

Preparation of conjugated dienoates with Bestmann ylide: Towards the synthesis of zampanolide and dactylolide using a facile linchpin approach

• Jingjing Wang,
• Samuel Z. Y. Ting and
• Joanne E. Harvey

Beilstein J. Org. Chem. 2015, 11, 1815–1822, doi:10.3762/bjoc.11.197

• products zampanolide and dactylolide is investigated using Bestmann ylide to link the C16–C20 alcohol with the C3–C8 aldehyde fragment. Keywords: Bestmann ylide; dactylolide; dienoate; (triphenylphosphoranylidene)ketene; zampanolide; Introduction (Triphenylphosphoranylidene)ketene, Ph3P=C=C=O (1), was

• . Although fragment syntheses vary, the late-stage fragment assembly of the dactylolide macrocycle has centred mostly around construction of the C1–C5 dienoate by Wittig-type olefination reactions followed by ester hydrolysis and esterification with the C19 hydroxy group, combined with metathesis to form the

• oct-2-en-1-ol (9b) with cinnamaldehyde (10a) was efficient and high yielding (Table 1, entry 3). Use of a Z-allylic alcohol 9c, likewise produced excellent amounts of the product dienoate (Table 1, entry 4), although a longer reaction time was required to achieve this. The Z-geometry of the allylic

Antioxidant potential of curcumin-related compounds studied by chemiluminescence kinetics, chain-breaking efficiencies, scavenging activity (ORAC) and DFT calculations

• Adriana K. Slavova-Kazakova,
• Silvia E. Angelova,
• Timur L. Veprintsev,
• Petko Denev,
• Davide Fabbri,
• Maria Antonietta Dettori,
• Maria Kratchanova,
• Vladimir V. Naumov,
• Aleksei V. Trofimov,
• Rostislav F. Vasil’ev,
• Giovanna Delogu and
• Vessela D. Kancheva

Beilstein J. Org. Chem. 2015, 11, 1398–1411, doi:10.3762/bjoc.11.151

• ), zingerone (3), (2Z,5E)-ethyl 2-hydroxy-6-(4-hydroxy-3-methoxyphenyl)-4-oxohexa-2,5-dienoate (4), ferulic acid (5) and their corresponding C2-symmetric dimers 6–9. Four models were applied: model 1 – chemiluminescence (CL) of a hydrocarbon substrate used for determination of the rate constants (kA) of the

• exclusively obtained at the olefinic double bond and keto–enol form was observed in solution by NMR spectroscopy for esters 4 and 8. (2Z,5E)-Ethyl 2-hydroxy-6-(4-hydroxy-3-methoxyphenyl)-4-oxohexa-2,5-dienoate (4) Monomer 4 was obtained following the known procedure with slight modifications [16]: To a

• -hydroxy-4-oxohexa-2,5-dienoate) (8) To a solution of sodium ethoxide (1.1 g, 15.7 mmol) in tetrahydrofuran (20 mL) was added dropwise a solution of 6 (1 g, 2.6 mmol) in THF (15 mL) at room temperature under an N2 atmosphere. The reaction mixture was stirred at room temperature for 10 min. Diethyl oxalate

Regioselective S_N2' Mitsunobu reaction of Morita–Baylis–Hillman alcohols: A facile and stereoselective synthesis of α-alkylidene-β-hydrazino acid derivatives

• Silong Xu,
• Jian Shang,
• Junjie Zhang and
• Yuhai Tang

Beilstein J. Org. Chem. 2014, 10, 990–995, doi:10.3762/bjoc.10.98

• procedures [46][47]. Benzyl 2-(hydroxymethyl)buta-2,3-dienoate (6) is a known compound and was prepared according to a literature [48]. Reagents from commercial sources were used without further purification. 1H and 13C NMR spectra were recorded on a Bruker AV 400 spectrometer in CDCl3 with tetramethylsilane

Asymmetric total synthesis of a putative sex pheromone component from the parasitoid wasp Trichogramma turkestanica

• Danny Geerdink,
• Jeffrey Buter,
• Teris A. van Beek and
• Adriaan J. Minnaard

Beilstein J. Org. Chem. 2014, 10, 761–766, doi:10.3762/bjoc.10.71

• Markiewicz, comprising a vinylogous Horner–Wadsworth–Emmons olefination, offered in principle a very efficient procedure to obtain dienoate 13 (Scheme 3), and would leave only a single step in the synthesis of 2 [25]. Therefore, reagent 12 was prepared in two steps. After quantitative conversion of 10 into

Synthesis of five- and six-membered cyclic organic peroxides: Key transformations into peroxide ring-retaining products

• Alexander O. Terent'ev,
• Dmitry A. Borisov,
• Vera A. Vil’ and
• Valery M. Dembitsky

Beilstein J. Org. Chem. 2014, 10, 34–114, doi:10.3762/bjoc.10.6

• , desilylation, and recyclization accompanied by a ring opening of oxirane or oxetane (Scheme 62 and Scheme 63). Cobalt(II) acetylacetonate (acac) or bis-2,2,6,6-tetramethylheptane-3,5-dienoate (thd) were used as the catalyst for the peroxidation of 219. The cyclization of the intermediate peroxide 220 was

Multigramme synthesis and asymmetric dihydroxylation of a 4-fluorobut-2E-enoate

• James A. B. Laurenson,
• John A. Parkinson,
• Jonathan M. Percy,
• Giuseppe Rinaudo and
• Ricard Roig

Beilstein J. Org. Chem. 2013, 9, 2660–2668, doi:10.3762/bjoc.9.301

• -fucose (13, shown) and 6-deoxy-6-fluoro-D-galactose (Scheme 2) [13]. The main challenges we faced included the synthesis of 9 and its bromide precursor 8 in acceptable yield and purity, and the unexpectedly low regioselectivity of AD reactions of the fluorinated dienoate. Methyl sorbate (7) underwent AD

Efficient syntheses of 25,26-dihydrodictyostatin and 25,26-dihydro-6-epi-dictyostatin, two potent new microtubule-stabilizing agents

• María Jiménez,
• Wei Zhu,
• Andreas Vogt,
• Billy W. Day and
• Dennis P. Curran

Beilstein J. Org. Chem. 2011, 7, 1372–1378, doi:10.3762/bjoc.7.161

• starting from commercially available pseudoephedrine amide 10. The syntheses of the bottom fragments 6a and 6b were achieved by applying the previously reported cross-metathesis reactions of readily available 20a,b with (2Z,4E)-methyl hexa-2,4-dienoate followed by silylation to provide 21a,b [39]. These

When cyclopropenes meet gold catalysts

• Frédéric Miege,
• Christophe Meyer and
• Janine Cossy

Beilstein J. Org. Chem. 2011, 7, 717–734, doi:10.3762/bjoc.7.82

• required harsher conditions (DCE, 80 °C), but the corresponding tetrasubstituted triene 54 was still obtained in good yield (77%). For the latter substrate, the reaction was conducted in an excess of 2-methylfuran and triene 55 was isolated in low yield (37%), accompanied by dienoate 56 as a by-product

Application of the diastereoselective photodeconjugation of α,β-unsaturated esters to the synthesis of gymnastatin H

• Ludovic Raffier and
• Olivier Piva

Beilstein J. Org. Chem. 2011, 7, 151–155, doi:10.3762/bjoc.7.21

• dienoate chain. The configuration at the C-2 carbon atom of this precursor was controlled by using a diastereoselective alkylation of an acyl oxazolidinone. In some cases, a Claisen condensation took place and afforded a β-ketoamide in noticeable amounts diminishing the overall yield of the sequence [15

Stereoselective synthesis of (2S,3S,4Z)-4-fluoro- 1,3-dihydroxy- 2-(octadecanoylamino)octadec- 4-ene, [(Z)-4-fluoroceramide], and its phase behavior at the air/water interface

• Gergana S. Nikolova and
• Günter Haufe

Beilstein J. Org. Chem. 2008, 4, No. 12, doi:10.3762/bjoc.4.12

• observed in compressed monolayers of ethyl (Z)-2-fluorooctadec-2-enoate [29] and ethyl (2E,4Z)-4-fluorooctadeca-2,4-dienoate [43]. Moreover, a very short C–H···F–C distance (2.30 Å) was observed in crystalline state for (Z)-2-amino-4-fluorododec-4-enecarboxylic acid [44]. Conclusion In this paper a short