Au-catalyzed tandem cyclization/[1,2]-alkyl migration reaction of epoxy alkynes: synthesis of spiropyranones.
A novel gold-catalyzed tandem cyclization/[1,2]-alkyl migration process of epoxy alkynes to spiropyranones has been discovered. From this process, the construction of adjacent multiple stereocenters with a new quaternary carbon atom is achieved. The gold-catalyzed domino process is stereospecific with respect to the migrating carbon atom. A type of unusual C-C bond cleavage of epoxide systems has also been discovered, which can lead to the formation of two Z alkenes and a carbonyl functional group in one step with excellent stereoselectivity. Furthermore, this efficient domino process could be achieved in the presence of the simplest and least expensive gold catalyst [NaAuCl(4)].2H(2)O with a low catalyst loading.
Shu
Xing-Zhong
XZ
State Key Laboratory of Applied Organic Chemistry, Lanzhou University, Lanzhou, PR China.
Liu
Xue-Yuan
XY
Ji
Ke-Gong
KG
Xiao
Hui-Quan
HQ
Liang
Yong-Min
YM