X=y-ZH compounds as potential 1,3-dipoles. part 44.1 asymmetric 1,3-dipolar cycloaddition reactions of imines and chiral cyclic dipolarophiles
摘要:
Metallo - 1,3-dipoles generated in situ from both aryl and aliphatic imines of a-amino esters by the action of silver salts and tertiary amines undergo cycloaddition at room temperature to 5R-(1'R, 2'S, 5'R-menthyloxyl) - 2(5H)-furanone and to N-acetyl-5R-isopropoxy-2(5H)-pyrrolone giving homochiral cycloadducts in good yield in all cases. pi-Interaction between the dipolarophile carbonyl group and the aryl group in the aryl imines is not required for good induction. The stronger the base the faster the cycloaddition with 2-t-butyl-1,1,3,3-tetramethylguanidine > DBU > NEt(3). X-Ray crystal structures of representative cycloadducts establish the absolute configuration of the pyrrolidine stereocentres.
X=y-ZH compounds as potential 1,3-dipoles. part 44.1 asymmetric 1,3-dipolar cycloaddition reactions of imines and chiral cyclic dipolarophiles
作者:Daniel M. Cooper、Ronald Grigg、Simon Hargreaves、Peter Kennewell、James Redpath
DOI:10.1016/0040-4020(95)00397-q
日期:1995.7
Metallo - 1,3-dipoles generated in situ from both aryl and aliphatic imines of a-amino esters by the action of silver salts and tertiary amines undergo cycloaddition at room temperature to 5R-(1'R, 2'S, 5'R-menthyloxyl) - 2(5H)-furanone and to N-acetyl-5R-isopropoxy-2(5H)-pyrrolone giving homochiral cycloadducts in good yield in all cases. pi-Interaction between the dipolarophile carbonyl group and the aryl group in the aryl imines is not required for good induction. The stronger the base the faster the cycloaddition with 2-t-butyl-1,1,3,3-tetramethylguanidine > DBU > NEt(3). X-Ray crystal structures of representative cycloadducts establish the absolute configuration of the pyrrolidine stereocentres.