Iron-Catalyzed Alkylzincation of Terminal Alkynes

Although carbozincation of terminal alkynes is a promising method for the synthesis of alkenylzinc reagents, many challenges, especially the chemo-, regio-, and stereoselectivity, remain to be addressed. Herein we report an operationally simple, mild method for iron-catalyzed alkylzincation of terminal alkynes to produce a diverse array of alkenylzinc compounds in high yields with high anti-Markovnikov selectivity and high cis stereoselectivity. Using this method, we realized a cis alkylzincation of terminal alkynes, and we demonstrated that the method has a wide substrate scope (being suitable for aryl-, alkenyl-, alkyl-, and heteroatom-substituted acetylenes) and good functional group tolerance. Because the C­(sp²)Zn bonds of the products can be readily transformed, the method provides a competitive alternative to traditional methods for the selective synthesis of trisubstituted olefins. The iron catalyst developed in this study exhibited irreplaceable reactivity in alkyne alkylzincation