Organocatalytic Asymmetric Synthesis of Spiro-Tetrahydrothiophene Oxindoles Bearing Four Contiguous Stereocenters by One-Pot Michael-Henry-Cascade-Rearrangement Reactions.

Asymmetric construction of tetrahydrothiophenes with four contiguous stereocenters remains a formidable challenge. Herein, the bottleneck was addressed by an unprecedented one-pot Michael-Henry-cascade-rearrangement reaction that could simultaneously create four consecutive stereogenic centers including two tetrasubstituted carbon stereocenters. The highly functionalized chiral spirotetrahydrothiophene scaffolds were assembled in moderate to good yields (≈54-79 %), excellent diastereo- (>20:1 d.r.) and enantio-selectivities (up to 93 % ee).