Patent ID: 8779179

Claim:
A process for preparing a compound of the formula where R 1 and R 2 are (hetero)hydrocarbyl groups, and R 1 is not R 2 , and y is 1 or 2, comprising the steps of: a) contacting a hydrocarbylsilane of the formula with an organometallic reagent of the formula R 2 -M m+ (X 1 ) m-1 , wherein M m+ an alkali- or alkali earth metal cation of valence m, where m is 1 or 2, X 1 is a halide, X is a halogen atom, and y is 1 or 2; b) brominating the product of step a) with a transition metal bromination catalyst and an aliphatic bromo compound; c) contacting the product of step b) with an organometallic compound of the formula where M+ is an alkali- or alkali earth metal cation, R 3 is H- or an acetylene protecting group, and where R 3 is an acetylene protecting group, removing the protecting group of the product of step c).