A modular approach to α-arylated carbonyl compounds via indium tris(bistriflylamide)-catalyzed regioselective addition of β-ketoesters to 1,3-diynes

Abstract

A modular synthesis of α-arylated carbonyl compounds has been achieved by the combination of an indium-catalyzed regioselective addition of β-keto esters to conjugated diynes and a palladium-catalyzed benzannulation reaction. Indium tris(bistriflylamide), In(NTf2)3, was found to be an efficient catalyst for the first addition reaction of β-keto esters to diynes. The reaction proceeds with perfect regioselectivity to give conjugated enynes in high yield. The second palladium-catalyzed benzannulation proceeds in high to excellent yield and with high regioselectivity for a variety of diynes. This two-step α-arylation of carbonyl compounds thus proceeds in a catalytic manner without loss of elements in the starting materials. The reaction may be performed in a single pot without isolation of the product of the first step. © 2005 Wiley-VCH Verlag GmbH & Co. KGaA.