Highly diastereoselective acetal cleavages using novel reagents prepared from organoaluminum and pentafluorophenol
作者:Kazuaki Ishihara、Naoyuki Hanaki、Hisashi Yamamoto
DOI:10.1021/ja00076a030
日期:1993.11
Chiral acetals derived from aldehydes and (-)-(2R,4R)-2,4-pentanediol are cleaved selectively by organoaluminum reagents. The reaction proceeds via the retentive-alkylation process with >95% selectivities in most cases. Trialkylaluminum reagent is utilized for higher alkyl transfers, but for smaller alkyl transfers, a new reagent system, combining trialkylaluminum and the halophenols such as pentafluorophenol
衍生自醛和 (-)-(2R,4R)-2,4-戊二醇的手性缩醛被有机铝试剂选择性裂解。在大多数情况下,反应通过保留性烷基化过程进行,选择性大于 95%。三烷基铝试剂用于更高的烷基转移,但对于较小的烷基转移,采用了一种新的试剂系统,结合了三烷基铝和卤代酚,如五氟苯酚和 2,4,6-三氯苯酚。衍生自醛和 1,3-丁二醇的手性缩醛被三烷基铝选择性裂解,即使是较小的烷基转移也是如此。氧杂环丁烷也暴露在这些铝试剂中,立体选择性地获得了保留性烷基化产物