Highly Enantioselective Intramolecular Cyanoamidation: (+)-Horsfiline, (−)-Coerulescine, and (−)-Esermethole
作者:Venkata Jaganmohan Reddy、Christopher J. Douglas
DOI:10.1021/ol902949d
日期:2010.3.5
octahydro-MonoPhos allowed the production of oxindoles with high enantioselectivities. Cyanoformamides bearing free N−H groups are now tolerated, potentially allowing protecting-group-free synthesis. Oxindole products of cyanoamidation are rapidly transformed into (+)-horsfiline, (−)-coerulescine, and (−)-esermethole.
The cyanoamidation of olefins was achieved. When N-(2-vinylphenyl)cyanoformamides were treated with palladium catalyst, intramolecular cyanoamidation took place to give corresponding 3,3-disubstituted oxindoles. P(t-Bu)(3) showed a remarkable effect on this reaction. When it was used with Pd(dba)(2), the reaction was completed in 15 min at 100 degrees C for many substrates. Furthermore, the enantioselective cyanoamidation was accomplished with Pd(dba)(2) and an optically active phosphoramidite to provide optically active 3,3-disubstituted oxindoles. Manipulation of the resulting oxindoles has been studied. (C) 2010 Elsevier Ltd. All rights reserved.