Davies Huw M L, Hedley Simon J, Bohall Brooks R
Department of Chemistry, University at Buffalo, The State University of New York, Buffalo, New York 14260-3000, USA.
J Org Chem. 2005 Dec 23;70(26):10737-42. doi: 10.1021/jo051747g.
[reaction: see text] C-H functionalization of benzyl silyl ethers by means of rhodium-catalyzed insertions of aryldiazoacetates can be achieved in a highly diastereoselective and enantioselective manner by judicious choice of chiral catalyst or auxiliary. The dirhodium tetraprolinates such as Rh2((S)-DOSP)4 have been widely successful as chiral catalysts in the C-H functionalization chemistry of aryldiazoacetates, but give poor enantioselectivity in the reactions of aryldiazoacetates with benzyl silyl ether derivatives. The use of (S)-lactate as a chiral auxiliary resulted in C-H functionalization with moderately high diastereoselectivity (79-88% de) and enantioselectivity (68-85% ee). The best results (91-95% de, 95-98% ee), however, were achieved using Hashimoto's Rh2((S)-PTTL)4 catalyst.
[反应：见正文] 通过明智地选择手性催化剂或助剂，借助铑催化的芳基重氮乙酸酯插入反应，苄基硅醚的C-H官能化可以以高度非对映选择性和对映选择性的方式实现。诸如Rh2((S)-DOSP)4之类的四脯氨酸二铑在芳基重氮乙酸酯的C-H官能化化学中作为手性催化剂已广泛取得成功，但在芳基重氮乙酸酯与苄基硅醚衍生物的反应中对映选择性较差。使用(S)-乳酸作为手性助剂导致C-H官能化具有中等较高的非对映选择性（79 - 88%的非对映体过量）和对映选择性（68 - 85%的对映体过量）。然而，使用桥本的Rh2((S)-PTTL)4催化剂可获得最佳结果（91 - 95%的非对映体过量，95 - 98%的对映体过量）。
