Cobalt-Catalyzed Chemo-, Regio-, Diastereo-, and Enantioselective Cascade Coupling of 1,1-Disubstituted Allenes and Aldehydes

A cobalt-catalyzed protocol for cascade coupling of 1,1-disubstituted allenes with aldehydes initiated by chemo-, regio-, diastereo-, and enantioselective oxidative cyclization of allenes and aldehydes followed by chemo-, regio-, and stereoselective addition of the resulting allyl-cobalt intermediates to the second molecule of aldehydes promoted by a chiral bisphosphine-cobalt complex is presented. Such processes represent an unprecedented reaction pathway for cobalt catalysis that enables simultaneous and precise incorporation two molecules of aldehydes onto the more sterically congested alkene of the allenes and construction of three stereogenic centers, delivering a range of enantioenriched 1,4-diols in up to 77% yield, >98:2 dr, and 98:2 er.