摘要 |
A process for preparing a compound of formula VI wherein R1 and R6 is hydrogen, substituted or unsubstituted alkyl substituted or unsubstituted aryl, or substituted or unsubstituted aralkyl; R5 is B(OR2)(OR3), or wherein R2 and R3 independently from each other represent substituted or unsubstituted alkyl, substituted or unsubstituted aryl, or substituted or unsubstituted aralkyl; or R2 and R3 cooperatively form a part of a 5- to 10-membered fused or unfused ring, optionally a chiral 5- to 10-membered fused or unfused ring; X is selected from Cl, Br, I; and * indicates a chiral center; is described. |