An easy synthesis of chiral sulfinyl allylic bromides and their use in the preparation of(R)S- and (S)S-2-p-tolylsulfinyl-1,3-alkadienes
作者:Eric Bonfand、Pascal Gosselin、Christian Maignan
DOI:10.1016/s0957-4166(00)80374-2
日期:1993.7
Condensation of (R)-vinyl-p-tolylsulfoxide anion on carbonyl compounds led directly to chiral allylic sulfinylalcohols 1. By treatment with NBS/Me2S, these alcohols 1 were converted into the rearranged primary allylic bromides 2 via SN2' displacement. Optically pure (R)- and (S)-2-p-tolylsulfinyl-1,3-alkadienes 3 resulted from the action of KOH/ROH upon these bromides 2 via E2' eliminations.
Asymmetric intermolecular Diels-Alder reactions of enantiopure sulfinyl-homo- and -hetero-dienes: Preliminary results.
Reaction of (E)-(+)-(R)-2-p-tolylsulfinyl-1,3-pentadiene 1 with maleimide afforded 3 as a single, enantiomerically pure adduct under very mild conditions. 3 resulted from exclusive endo approach by a completely diastereofacialselective route. On the other hand, heterodiene (+)-(S)-3-p-tolylsulfinyl-3-buten-2-one 2 smoothly reacted with sensitive 2-methylenetetrahydrofuran yielding 1:1 diastereomeric dioxaspirodducts 4a and 4b, readily separated by liquid chromatography.
The Diels–Alder Adduct of an Enantiopure 2-Sulfinyldiene and Maleimide: (1S,2R,3S,SR)-3-Methyl-5-p-toluenesulfinylcyclohex-4-en-1,2-dicarboximide
作者:P. Gosselin、E. Bonfand、C. Maignan、R. Retoux
DOI:10.1107/s0108270194007304
日期:1995.1.15
The title compound, C16H17NO3S, is the single adduct obtained by cycloaddition of (E)-(+)-(R)-2-p-toluenesulfinyl-1,3-pentadiene with maleimide. The absolute configuration of the stereocentres is established and some mechanistic aspects are deduced.