Organocatalytic Asymmetric Synthesis of Tertiary Alkyl Chlorides

Significance

An organocatalytic asymmetric synthesis of tertiary alkyl chlorides has been developed. Planar chiral (-)-PPY^* (3 mol%) mediates the addition of 2,2,6,6-tetrachlorocyclohexanone (2) to ketenes 1 to give tertiary α-chloro esters 3 in good yields and enantioselectivities. Enol ester 4 has been transformed into the corresponding methyl ester 5 and alcohol 6 in acceptable yields and with preservation of the stereochemistry. Furthermore, mechanistic considerations based on NMR spectroscopy and experimental data are pro­vided.