The First General, Efficient and Highly Enantioselective Reduction of Quinoxalines and Quinoxalinones
作者:Magnus Rueping、Francisco Tato、Fenja. R. Schoepke
DOI:10.1002/chem.200902907
日期:——
Simple yet efficient: A series of diverse substituted tetrahydroquinoxalines and dihydroquinoxalinones have been synthesized for the first time in a highly enantioselective fashion (see scheme). Using this metal‐free hydrogenation it is possible to isolate these products, which are of high pharmaceutical interest, in good yields and with excellent enantioselectivities in a minimal number of reaction
together! A selective Fe‐catalysed enantioselective reduction of quinoxalines and benzoxazines with hydrogen is demonstrated. Key to success is the combination of a chiral Brønsted acid and a well‐defined non‐chiral Fe hydrogenation catalyst. This methodology constitutes an attractive and environmentally favourable alternative to well‐established asymmetric hydrogenations by using precious‐metal‐based catalysts