1,1-Carboboration of 1-Alkynes: A Conceptual Alternative to the Hydroboration Reaction
摘要:
Strongly electrophilic boranes R-B(C6F5)(2) react readily with a variety of 1-alkynes by means of a 1,1-carboboration reaction to yield alkenylborane products, which can subsequently be used as reagents in metal catalyzed cross-coupling reactions.
We have developed a nickel-catalyzedcross-coupling reaction of cyclic alkenyl ethers with arylboronic esters that leads to the formation of unsaturated alcohols via ring-opening by the cleavage of a C(sp2)–O bond. The use of 1,3-dicyclohexylimidazol-2-ylidene as the ligand is essential to promote this cross-coupling process.