A thiazazincolidine complex, 1, was shown to be an excellent catalyst for enantioselective reduction with bis(2,6-dimethylphenoxy)borane (BDMPB) of meso N-phenylimides in high ee to the corresponding hydroxy lactams, which were eventually converted to the corresponding lactones of high optical purity.
Stereoselective Synthesis of δ-Lactones from 5-Oxoalkanals via One-Pot Sequential Acetalization, Tishchenko Reaction, and Lactonization by Cooperative Catalysis of Samarium Ion and Mercaptan
作者:Jue-Liang Hsu、Jim-Min Fang
DOI:10.1021/jo016058t
日期:2001.12.1
sequence of acetalization, Tishchenko reaction and lactonization. The deliberative use of mercaptan, by comparison with alcohol, is advantageous to facilitate the catalytic cycle. The reaction mechanism and stereochemistry are proposed and supported by some experimental evidence. Such samarium ion/mercaptan cocatalyzed reactions show the feature of remote control, which is applicable to the asymmetric synthesis