Highly general synthesis of [E]- and [Z]-3-alkylsubstituted allylboronates via one-carbon homologation of stereospecific 1-alken-1-ylboronates

Abstract Stereospecific 1-alken-1-ylboronates readily react with in situ generated chloromethyllithium, producing the corresponding allylboronate in good yields and in excellent stereochemical purities. These are very important synthetic intermediates and conversion of a representative derivative, [ E ]-2-(2-heptenyl)-1,3,2-dioxaborinane, 2 (R 1 = C 4 H 9 , R 2 = R 3 = H), into several compounds of synthetic interest is described.