Organocatalytic Synthesis of Alkynes.

Carbon-carbon triple bonds of alkynes are ubiquitous. They serve as valuable starting materials that can be transformed into a vast array of diverse materials, with applications ranging from medicinal chemistry to electronic materials. The methods used to prepare alkynes involve stoichiometric reactions and the most popular install only a single carbon rather than uniting larger fragments. These methods are useful, but they are limited by harsh conditions or the need to prepare reagents. Introduced herein is the first catalytic method to prepare carbon-carbon triple bonds from precursors that do not contain such linkages. By coupling benzaldehyde and benzyl chloride derivatives under basic conditions with an organocatalyst, good yields of alkynes are obtained. The catalyst, a highly reactive sulfenate anion, is readily generated under the reaction conditions from air-stable precursors. This method represents an attractive organocatalytic alternative to well-established stoichiometric approaches to alkynes and to transition-metal-based alkyne functionalization methods in various applications.