Regio- and stereocontrolled access to γ-boronated unsaturated amino esters and derivatives from (Z)-alkenyl 1,2-bis(boronates).

Abstract : The Borono-Mannich reaction of (Z)-1-alkene-1,2-diboronic esters proceeded regioselectively at the terminal C-B bond to afford (E)-γ-boronated unsaturated amino esters in good yields. These compounds were then subjected to Suzuki couplings for the creation of diversely substituted olefinic amino acid systems. Several other functional transformations were also carried out to illustrate the synthetic utility of the Petasis products.