作者:Xiben Li、Dennis P. Curran
DOI:10.1021/ol902808m
日期:2010.2.5
reduction of the corresponding (E) amide rotational isomer under identical conditions provides only the reduced product, (E)-N-allyl-N-(2,4,6-tri-tert-butylphenyl)acetamide. Such diverging reactions of rotamers may be common in transformations involving reactive intermediates (carbenes, radicals, organometallic intermediates) that have low barriers to onward reactions relative to amide rotation.
通过分离旋转酰胺,然后使其分别反应,已观察到一对酰胺旋转异构体的化学选择性反应不同。的减少(Ž) - ñ -烯丙基-2-(phenylselanyl) - ñ - (2,4,6-三-叔丁基苯基)乙酰胺用氢化三丁基锡在室温下仅提供5-的产品外切环化,4-甲基-1-(2,4,6-三-叔丁基苯基)吡咯烷-2-酮。相反,在相同条件下还原相应的(E)酰胺旋转异构体只会提供还原的产物(E)-N-烯丙基-N-(2,4,6-三叔丁基-丁基苯基)乙酰胺。在涉及反应性中间体(卡宾,自由基,有机金属中间体)的转化中,旋转异构体的这种发散反应可能是常见的,所述中间体相对于酰胺旋转对前进反应具有较低的障碍。