Highly stereoselective synthesis of cis-alkenyl pinacolboronates and potassium cis-alkenyltri-fluoroborates via a hydroboration/protodeboronation approach

The development of a mild and general method for the synthesis of cis-alkenyl pinacolboronates and potassium organotrifluoroborates with corresponding terminal alkynes as starting material is reported. The alkynyl pinacolboronates bearing various functional groups are stereoseletively reduced to the cis-alkenyl pinacolboronates via hydroboration with dicyclohexylborane.