Irradiation of 1-acetyl-1,2-dihydroquinoline-2-carbonitrile (1) in ether gave the 3,1-benzoxazine (3b), while the 4-methyl congener (2) in either ether or ethanol gave the 3,1-benzoxazine (4b) and the cycloprop[b]indole (7). A possible mechanism for the formation of these products is also discussed.
Enantioselective Cyclopropanation of Indoles: Construction of All-Carbon Quaternary Stereocenters
作者:Gülsüm Özüduru、Thea Schubach、Mike M. K. Boysen
DOI:10.1021/ol302388t
日期:2012.10.5
The first enantioselective copper-catalyzed cyclopropanation of N-acyl indoles is described. Using carbohydrate-basedbis(oxazoline) ligands (glucoBox), the products were obtained in up to 72% ee. Cyclopropanation of N-Boc 3-methyl indole yielded a product with an all-carbon quaternary stereocenter, which is a valuable building block for the synthesis of indole alkaloids: Deprotection and rearrangement