23284-23-3

Upstream product

• 120040-63-3 (-)-(2R,3R,4S)-2-(Benzyloxy)-3-<(3,4,5-trimethoxyphenyl)bis(phenylthio)methyl>-4-<3,4-(methylendioxy)benzoyl>tetrahydrofuran 
• 61946-94-9 N-hydroxy-benzo[1,3]dioxole-5-carboximidoyl chloride 
• 86-81-7 3,4,5-trimethoxy-benzaldehyde 
• 120040-58-6 Benzo[1,3]dioxol-5-yl-((S)-5-benzyloxy-2,5-dihydro-furan-3-yl)-methanol 
• 120040-60-0 (+)-(2S)-2-(Benzyloxy)-2,5-dihydro-4-<3,4-(methylenedioxy)benzoyl>furan 
• 120040-61-1 5--1,2,3-trimethoxybenzene 
• 104322-42-1 (-)-(2S)-benzyloxy-2,5-dihydrofuran-4-carboxaldehyde 
• 2635-13-4 1,2-(methylenedioxy)-4-bromobenzene 
• 147200-49-5 (3R,4R)-3-Hydroxy-4-<3,4-(methylenedioxy)benzyl>tetrahydrofuran 
• 123731-52-2 3,4,5-trimethoxybenzyl phenyl sulfide 
• 6267-80-7 (3S,4S)-4-[(RS)-1-(1,3-benzodioxol-5-yl)-1-hydroxymethyl]-3-(3,4,5-trimethoxybenzyl)tetrahydro-2-furanone 
• 72690-16-5 (3S,4S)-4-(benzo[d][1,3]dioxol-5-ylmethyl)-3-(3,4,5-trimethoxybenzyl)dihydrofuran-2(3H)-one 
• 72627-53-3 (+)-dihydroclusin 

Relevant academic research and scientific papers

A general approach to the asymmetric synthesis of lignans: (-)-methyl piperitol, (-)-sesamin, (-)-aschantin, (+)-yatein, (+)-dihydroclusin, (+)-burseran, and (-)-isostegane

A highly efficient, diastereo- and enantioselective route was developed to access a great variety of lignans. The asymmetric synthesis of the 2,3-disubstituted γ-butyrolactones 9a-c could be improved in the case of aldol reactions by employing 2.2 equivalents of LiCl as an additive to provide, after purification, highly diastereo- and enantioenriched starting materials for the synthesis of the furofuran lignans (-)-methyl piperitol, (-)-sesamin, and (-)-aschantin. Furthermore, the γ-butyrolactone 15 was converted into dibenzylbutyrolactone lignan (+)-yatein, the dibenzylbutandiol type (+)-dihydroclusin, the tetrahydrofuran type (+)-burseran, and the dibenzocyclooctadiene type (-)-isostegane.

Enantiocontrolled Synthesis of Burseran, Brassilignan, Dehydroxycubebin, and Other Tetrahydrofuran Lignans in Both Enantiomeric Forms. Application of Intermolecular Nitrile Oxide Cycloadditions and Lipase Mediated Kinetic Resolutions

Several natural and unnatural tetrahydrofuran lignans have been synthesized by a convergent approach.Our methodology utilizes a nitrile oxide cycloaddition to dihydrofuran 8 and an enzymatic resolution of alcohols 11 by lipase PS.The lipase-mediated kinetic resolution of alcohols 11 furnished both enantiomers of the lignan precursors 12 and 14 in high optical purity (>99percent ee).This is followed by a SN2 displacement of tosylates 15 and 18 by α-lithiobenzyl phenyl sulfides.In this manner, both enantiomers of 3,4-dibenzyltetrahydrofuran (17a, 20a), 3,4-bis(3-methoxybenzyl)tetrahydrofuran (17b, 20b), brassilignan (17c, 20c), dehydroxy cubebin (17d, 20d), and burseran (17e, 20e) were synthesized in overall yields of 6-16percent.

General Conjugate-Addition Method for the Synthesis of Enantiomerically Pure Lignans. Total Synthesis of (-)- and (+)-Burseran, (-)-Dehydroxycubebin, (-)-Trichostin, (-)-Cubebin, (-)-5''-Methoxyhinokinin, and (-)-Hinokinin

Conjugate addition of benzylic diphenyldithioacetal anions to enantiomerically pure (-)-(2R)-and (+)-(2S)-(benzyloxy)-2,5-dihydro-4-furan (2 r and 2 s) gave complete lignan skeletons of the dibenzylbutane class.Desulfurization followed by hydrogenolysis and, when appropriate, oxidation gave the title enantiomerically pure > 99 percent ee) lignans 45 - 50 in 24 - 35 percent overall yields from 2 r and 2 s.