Organocatalytic Asymmetric Synthesis of Pentasubstituted Tetrahydrothiopyrans Bearing a Quaternary Centre through a Double Michael Reaction
作者:Subhas Pan、Buddhadeb Mondal
DOI:10.1055/s-0036-1591736
日期:2018.3
An organocatalytic, asymmetric, double-Michael strategy has been developed employing trans-α-cyano-α,β-unsaturated ketones for the synthesis of pentasubstituted tetrahydrothiopyrans bearing a quaternary center. A proline-derived bifunctional thiourea was found to be the most effective catalyst for this reaction. With 10 mol% of catalyst, good yields and good to high diastereomeric ratios, as well as
While phosphine-mediated reactions have been extensively explored over the past few decades, the catalytic cyclopropanation reaction via a phosphonium ylide pathway has been significantly underdeveloped, and an intermolecular version still remains to be disclosed. Presented herein is a catalytic cyclopropanation reaction between readily available benzylbromides and activated alkenes, such as α-cyano