Pseudo‐Stereodivergent Synthesis of Enantioenriched Tetrasubstituted Alkenes by Cascade 1,3‐Oxo‐Allylation/Cope Rearrangement

The catalytic diastereodivergent construction of stereoisomers having two or more stereogenic centers has been extensively studied. In contrast, the switchable introduction of another stereogenic element, that is, Z/E configuration involving a polysubstituted alkene group, into the optically active stereoisomers, has not been recognized yet. Disclosed here is the pseudo‐stereodivergent synthesis of highly enantioenriched tetrasubstituted alkene architectures from isatin‐based Morita–Baylis–Hillman carbonates and allylic derivatives, under the cooperative catalysis of a tertiary amine and a chiral iridium complex. The success of the switchable construction of the tetrasubstituted alkene motif relies on the diastereodivergent 1,3‐oxo‐allylation reaction between N‐allylic ylides and chiral π‐allyliridium complex intermediates by ligand and substrate control, followed by the stereoselective concerted 3,3‐Cope rearrangement process. All possible stereoisomers: The switchable pseudo‐stereodivergent synthesis of enantioenriched tetrasubstituted alkenes from isatin‐based Morita–Baylis–Hillman carbonates and allylic benzoates was developed under the cooperative catalysis of a tertiary amine and a chiral iridium complex, through a diastereodivergent 1,3‐oxo‐allylation reaction and a stereoselective 3,3‐Cope rearrangement. All four possible stereoisomers are constructed with excellent enantioselectivities.