+ 3] annulation of 1-methylindoline-2-thiones and 4-arylmethylideneoxazolin-5(4H)-ones has been developed by the use of an L-tert-leucine-derived bifunctional tertiary amine-squaramide catalyst, which furnished a series of optically active conformationally strained β-branched cyclic tryptophan derivatives in acceptable yields with good to excellent diastereo- and enantioselectivities.
对映体选择性正式[3 + 3]的
1-甲基吲哚啉-2-
硫酮环和4- arylmethylideneoxazolin-5(4 ħ) -酮已经开发通过使用的大号-叔-亮
氨酸衍生的双官能叔胺催化剂squaramide ,以可接受的收率提供了一系列旋光性构象应变的β-支化环状色
氨酸衍
生物,具有良好至优异的非对映选择性和对映选择性。