Ethene/alkyne exchange reaction at an intramolecular frustrated Lewis pair

Abstract

A vicinal ethylene bridged S/B frustrated Lewis pair (FLP) in situ generated by a hydroboration reaction of phenyl vinyl sulfide, reacts with p-tert-butylphenylacetylene by ethene/alkyne exchange and subsequent 1,2-addition of a second alkyne equivalent to give a zwitterionic sulfonium/borate product.