One‐Pot Carboboration of Alkynes Using Lithium Borylcyanocuprate and the Subsequent Suzuki–Miyaura Cross‐Coupling of the Resulting Tetrasubstituted Alkenylborane

Abstract

Abstract We have developed a one‐pot carboboration of internal alkynes using lithium borylcyanocuprates 3 . Isolation of single crystals of 3· (thf) 3 enabled us to estimate its structural and spectroscopic features. Simple mixing of 3 with ester‐substituted alkynes and alkynylarenes was followed by trapping of the resulting intermediate with electrophiles to give tetrasubstituted borylalkenes 4 , 5 , and 8 in moderate to good yields. Ligand exchange of 8ba from diamine to pinacol allowed us to explore further application of obtained pinacol ester 10ba to subsequent Suzuki–Miyaura cross‐coupling reactions to give all‐carbon substituted alkene 9ba .