Reversible Alkylation of Dimedone with Aldehyde: A Neglected Way for Maximizing Selectivity of Three‐Component Reactions of Dimedone and an Aldehyde
作者:Minghao Li、Yanlong Gu
DOI:10.1002/adsc.201200299
日期:2012.9.17
selectivity of a three‐component electrophilic reaction of an aldehyde with dimedone and another carbon‐based nucleophile could be improved by a reversible alkylation procedure, which involves formation, breaking and regeneration of CC bonds. In the presence of iron(III) chloride and triphenylphosphine, an analogous CC bond breaking can be observed in the reaction of 2,3,4,9‐tetrahydro‐9‐(2‐hydroxy‐4,4‐
醛与二甲酮和另一种基于碳的亲核试剂的三组分亲电反应的选择性可以通过可逆的烷基化程序来改善,该程序涉及CC键的形成,断裂和再生。在氯化铁(III)和三苯膦存在下,在2,3,4,9-四氢-9-(2-羟基-4,4-二甲基-6的反应中可以观察到类似的CC键断裂-oxo-1-cyclohexen-1-yl)-3,3-二甲基-1 H -xanthen-1-one,其中二甲酮的片段被碳基亲核试剂所取代。受此观察结果的启发,使用氯化铁(III)和三苯膦(PPh 3)作为催化剂。PPh 3起到氢键受体的作用,它通过减弱分子内的氢键赋予底物良好的柔韧性,从而使底物易于与氯化铁(III)相互作用。