C-Allylation of Propargyl and Benzhydryl Alcohols with Allylsilanes

Significance

This work offers a simple method for the C-allylation of the carbocations formed from several kinds of benzhydryl and propargyl alcohols by their reaction with allyl silanes. It is a simple method for the construction of rather complex carbon frameworks from relatively trivial precursors. This method applies an interesting methodology: generation of the corresponding carbocation directly from an alkoxide by reaction with boron trichloride. Benzhydryl cations generated this way may also react with alkynes, affording polysubstituted alkenes. This reaction was difficult to perform using Brønsted acid catalysts due to competitive side reactions of the alkyne.