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Uncatalysed (thermal) and Lewis acid-promoted asymmetric hetero-Diels-Alder reaction of 1-thiabuta-1,3-dienes (thiochalcones) with di-(-)-menthyl fumarate. Configuration determination by X-ray crystallographic analysis of (2S,3R,4R)-(+)-2,3-bis[(-)-menthoxycarbonyl]-4,6-diphenyl-3,4-dihydro-2H- thiopyran and conversion of cycloadducts into optically pure diols

DOI: 10.1039/P19960001897

Source and publish data:

Journal of the Chemical Society. Perkin transactions I p. 1897 - 1903 (1996)

Update date:2022-08-03

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Authors:

Saito, TakaoSaito, Takao

Fujii, HironariFujii, Hironari

Hayashibe, SatoshiHayashibe, Satoshi

Matsushita, TerukiMatsushita, Teruki

Kato, HideoKato, Hideo

Kobayashi, KimikoKobayashi, Kimiko

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Article abstract of DOI:10.1039/P19960001897

1-Thiabuta-1,3-dienes 1 (thiochalcones) underwent asymmetric hetero-Diels-Alder reaction with di-(-)-menthyl fumarate 2 to afford a mixture of 3,4-cis- (3 and 4) and 3,4-trans-dihydrothiopyrans (5 and 6) in good-to-excellent chemical yield with fair diastereoselectivities, the stereoisomer 3 predominating. An endo (3,4-cis) : exo (3,4-trans) selectivity was observed in the ratio 98-85:2-15. The uncatalysed reaction at 20-40°C showed 10-48% de in diastereo-π-facial selectivity, while the selectivity was improved to 62-71% de by using a suitable Lewis acid under appropriate reaction conditions. The 3,4-cis-stereoisomer formed favourably in both thermal and Lewis acid-promoted reactions, had the same configuration 2S,3R,4R (3). The configuration was unequivocally established by X-ray crystallographic structural analysis using the isomer 3a (R1 = R2 = Ph). The isomer 3, which could be obtained stereochemically homogeneous by chromatography and recrystallization, was consecutively transformed to optically pure diols 7 and 8 or 9 by LiAlH4 reduction, followed by reductive desulfurization with Raney Ni.

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Product name:(2S,3R,4R)-4,6-Di-thiophen-2-yl-3,4-dihydro-2H-thiopyran-2,3-dicarboxylic acid bis-((1R,2S,5R)-2-isopropyl-5-methyl-cyclohexyl) ester

Cas No:182127-14-6

182127-14-6

R&D Labs maybe for 182127-14-6

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