Zinc-Mediated Asymmetric Additions of Dialkylphosphine Oxides to α,β-Unsaturated Ketones and N-Sulfinylimines
摘要:
A catalyst was synthesized on the basis of Trost's dinuclear catalyst characterized by working well without pyridine in the present phospha-Michael reaction Nevertheless, the presence of pyridine is still advantageous in the present system The substrate scope was successfully extended to enones employing diallyl phosphine oxide as a nucleophile Excellent yields and enantioselectivities (up to >99% ee) wine achieved for a wide scope of enones employing the catalyst under mild conditions The detailed reaction mechanism is also discussed hetein Finally. the unprecedented asymmetric additions of dialkylphosphine oxides to N-sulfinylumines were achieved by using Et2Zn as a base
Asymmetric synthesis of trifluoromethylated propargylamines via 1,2-additions of trifluoromethylacetylide to N-tert-butanesulfinyl imines
作者:Xian-Yin Chen、Xiao-Long Qiu、Feng-Ling Qing
DOI:10.1016/j.tet.2008.01.021
日期:2008.3
An efficient method for the asymmetric synthesis of the trifluoromethylated propargylamines was described. Addition of lithium trifluoromethylacetylide, in situ prepared from lithium diisopropylamide and the 2-bromo-3,3,3-trifluoropropene, to various N-tert-butanesulfinylimines provided a range of trifluoromethylated propargyl sulfinamides. Besides high yields and excellent diastereoselectivities