title: Gold(I)-catalyzed diastereoselective hydroacylation of terminal alkynes with glyoxals.
abstract: The reaction of an α-ketoaldehyde and a terminal alkyne in the presence of piperidine and a catalytic amount of AuCl delivers 1,2-dicarbonyl-3-enes, products of the formal hydroacylation of the triple bond. The scope of the method is broad; different aryl substituents on the dicarbonyl unit and on the alkyne are well tolerated. The products can be transformed selectively into vinylquinoxalines. Mechanistic studies, including isotope-labeling experiments, indicate that after an initial A(3) -type conversion to propargylic amines, a subsequent base-mediated alkyne-to-allene isomerization and a hydrolysis of the enamine substructure during the workup deliver the formal hydroacylation products.
authors: Organisch-Chemisches Institut, Ruprecht-Karls-Universität Heidelberg, Im Neuenheimer Feld 270, 69120 Heidelberg (Germany) http://www.hashmi.de.
authors: Shuai
authors: S
authors: Shi
authors: Tao
authors: T
authors: Wang
authors: Vanessa
authors: V
authors: Weingand
authors: Matthias
authors: M
authors: Rudolph
authors: A Stephen K
authors: AS
authors: Hashmi
keywords: 1,2-dicarbonyl compounds; Michael acceptors; alkynes; gold; quinoxaline