Rhodium-Catalyzed Asymmetric 1,4-Addition of Heteroaryl Triolborates

Significance

The authors describe a rhodium-catalyzed asymmetric 1,4-addition of pyridyl and thiophenyl triolborates to α,β-unsaturated carbonyl compounds. The scope is good for neutral and electron-rich heteroaryl triolborates and cyclic and acyclic enones. When the heteroatom is adjacent to the triolborate, only traces of product are seen except if ortho-blocking groups are present.