Tunable and highly regio- and diastereoselective vinylogous Mannich-type reaction of dioxinone-derived silyl dienolate.

ABSTRACT

A tunable and highly regio- and diastereoselective vinylogous Mannich-type reaction of dioxinone-derived silyl dienolate (1) with chiral N-tert-butanesulfinyl imino ester (2) was developed. By appropriate choice of Lewis acid catalyst, two diastereomers of the gamma-product were obtained, respectively, with dr up to 955. The procedure for the Ag(I)-catalyzed vinylogous Mannich-type reaction also provided facile access to the alpha-regioisomer with excellent diastereoselectivities (up to >991 dr) by changing the counterion of the Ag(I) salt.