Heteroarylboronates in rhodium-catalyzed 1,4-addition to enones.

摘要: Rhodium(I)-catalyzed 1,4-addition of aryl and alkenylboronic acids to α,β-unsaturated carbonyl compounds is well established, but the transfer heteroaryl residues in this reaction remains underdeveloped. We have studied MIDA pinacol boronates as alternatives labile boronic acid counterparts. Under racemic conditions, 12 adducts with residues, among them unsubstituted 3- 4-pyridinyl, 2-furanyl, thienyl, pyrrolyl groups, were obtained moderate excellent yields. The enantioselective version proved highly sensitive electronic character substituents, carrying electron-rich giving modest high yields consistently enantiomeric excesses.