Conjugate Addition of Organocuprates to Chiral Bicyclic δ-Lactams. Enantioselective Synthesis of <i>cis</i>-3,4-Disubstituted and 3,4,5-Trisubstituted Piperidines
作者:Mercedes Amat、Maria Pérez、Núria Llor、Joan Bosch、Elena Lago、Elies Molins
DOI:10.1021/ol007010p
日期:2001.2.1
[reaction: see text] Chiral nonracemic bicyclic lactam 3, easily accessible by cyclodehydration of (R)-phenylglycinol and racemic methyl 4-formylhexanoate, was converted to the unsaturated lactams 5, which undergo the stereoselective conjugate addition of lower order cyanocuprates to ultimately lead to enantiopure cis-3,4-disubstituted and 3,4,5-trisubstituted piperidines.
[反应:见正文]手性非外消旋双环内酰胺3,可通过(R)-苯基甘氨醇和外消旋4-甲酰基己酸酯的环脱水反应轻松获得,被转化为不饱和内酰胺5,内酰胺5经过立体选择性共轭添加了低级的氰尿酸酯,最终导致对映体纯的顺式-3,4-二取代和3,4,5-三取代的哌啶。