E-selective hydroboration of alkynes catalyzed by 3N-donor Schiff-base cobalt(II) complex
Piotr Andruszak, Piotr Pawluć, Maciej Kubicki, Maciej Zaranek
Abstract
• A five-coordinated cobalt(II) Schiff-base complex is reported as alkyne hydroboration catalyst. • Hydroboration proceeds with excellent efficiency and selectivity toward β- ( E ) addition products. • Easy work-up allows for isolation of products with yields up to 97%. Hydroboration is one of the landmark reactions of homogeneous catalysis. Despite the existence of many mature protocols, there is still a field for the search of new ones, especially utilizing active and selective base-metal catalysts. We report an effective and selective method for anti-Markovnikov hydroboration of alkynes using bench-stable cobalt(II) complex bearing a 3 N -donor Schiff-base ligand. The optimized procedure can be used both on aromatic and aliphatic alkynes leading to high yields of fully selective transformations within 90 min at room temperature.