Stereoselective Csp³ -Csp² Cross-Couplings of Chiral Secondary Alkylzinc Reagents with Alkenyl and Aryl Halides.

ABSTRACT: We report palladium-catalyzed cross-coupling reactions of chiral secondary non-stabilized dialkylzinc reagents, prepared from readily available chiral secondary alkyl iodides, with alkenyl and aryl halides. This method provides α-chiral alkenes and arenes with very high retention of configuration (dr up to 98:2) and satisfactory overall yields (up to 76 % for 3 reaction steps). The configurational stability of these chiral non-stabilized dialkylzinc reagents was determined and exceeded several hours at 25 °C. DFT calculations were performed to rationalize the stereoretention during the catalytic cycle. Furthermore, the cross-coupling reaction was applied in an efficient total synthesis of the sesquiterpenes (S)- and (R)-curcumene with control of the absolute stereochemistry.

SUBMITTER: Skotnitzki J 

PROVIDER: S-EPMC6973128 | biostudies-literature | 2020 Jan

REPOSITORIES: biostudies-literature