Enantioselective Binaphthophosphepine-Promoted [3+2] Annulations of N-Ts- and N-DPP-Imines with Allenoates and 2-Butynoates
作者:Nathalie Pinto、Nicolas Fleury-Brégeot、Angela Marinetti
DOI:10.1002/ejoc.200800598
日期:——
The use of binaphthophosphepine 1a as a catalyst for the [3+2] cyclisation between allenoates or 2-butynoates andimines was investigated. The effects of the imine protecting group on both the catalytic activity and enantioselectivity were determined by comparing the behaviour of N-tosyl- and N-DPP-imines. The N-DPP-imines displayed lower reactivity, but afforded the desired pyrrolines in higher enantiomeric
研究了双萘膦 1a 用作烯丙酸酯或 2-丁酸酯和亚胺之间 [3+2] 环化的催化剂。通过比较 N-甲苯磺酰基-和 N-DPP-亚胺的行为,确定亚胺保护基团对催化活性和对映选择性的影响。N-DPP-亚胺表现出较低的反应性,但以更高的对映体过量(73-92%ee)提供所需的吡咯啉。在温和条件下从最终的吡咯啉中除去 DPP 保护基团,得到相应的仲胺。(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)