Dehydrogenative Cyclocondensation of Aldehydes, Alkynes, and Dialkylsilanes

The nickel-catalyzed coupling of aldehydes, alkynes, and dialkylsilanes results in an unusual dehydrogenative cyclocondensation process to afford five-membered silacyclic products. The process allows dialkylsilanes to serve as a silylene synthetic equivalent. A mechanistic pathway for the process involving the formation of an aldehyde/alkyne-derived nickel metallacycle followed by sequential sigma-bond metathesis processes involving the two Si-H bonds has been proposed.