Pd3(dppm)3(CO)2+簇合物：一种用于酰氯氟化和醇解的高效电化学辅助路易斯酸催化剂。

The Pd3(dppm)3(CO)2+ cluster: an efficient electrochemically assisted Lewis acid catalyst for the fluorination and alcoholysis of acyl chlorides.

作者信息

Lemaître Frédéric, Lucas Dominique, Mugnier Yves, Harvey Pierre D

机构信息

Laboratoire de Synthèse et d'Electrosynthèse Organométalliques, CNRS UMR 5632, Faculté des Sciences Gabriel, Université de Bourgogne, 6 Boulevard Gabriel, 21000 Dijon, France.

出版信息

J Org Chem. 2002 Oct 18;67(21):7537-40. doi: 10.1021/jo026237q.

DOI:10.1021/jo026237q

PMID:12375992

Abstract

The dicationic palladium cluster Pd3(dppm)3(CO)2+ (dppm = bis(diphenylphosphino)methane) reacts with acid chlorides RCOCl (R = n-C6H13, t-Bu, Ph) to afford quantitatively the chloride adduct Pd3(dppm)3(CO)(Cl)+ and the acyl cation RCO+ as the organic counterpart. The dicationic reactive cluster can be reformed by electrolyzing the chloride complex with a copper anode leaving CuCl as a byproduct. The combination of these two reactions provides an electrocatalytic way to form the acylium from the acid chloride. Indeed, in CH2Cl2, 0.2 M NBu4PF6, or NBu4BF4, the electrolysis of the acid chloride in the presence of a catalytic amount of the cluster (1%) gives in good yields the acid fluoride RCOF, arising from the coupling of the acylium with a F(-) issued from the fluorinated supporting electrolyte. Alternatively, in CH2Cl2 or 0.2 M NBu4ClO4, by operating with an alcohol R'OH as the nucleophile, the electrolysis gives the ester RC(O)OR' as the only final product.

摘要

二价钯簇合物Pd3(dppm)3(CO)2+（dppm = 双（二苯基膦基）甲烷）与酰氯RCOCl（R = 正己基、叔丁基、苯基）反应，定量生成氯加合物Pd3(dppm)3(CO)(Cl)+和作为有机对应物的酰基阳离子RCO+。通过用铜阳极电解氯化物络合物可将二价活性簇合物重新生成，同时副产CuCl。这两个反应的结合提供了一种从酰氯形成酰鎓离子的电催化方法。实际上，在二氯甲烷、0.2 M四丁基六氟磷酸铵或四丁基四氟硼酸铵中，在催化量的簇合物（1%）存在下电解酰氯，可高产率得到酰氟RCOF，它是由酰鎓离子与氟化支持电解质产生的F(-)偶联而成。或者，在二氯甲烷或0.2 M四丁基高氯酸铵中，以醇R'OH作为亲核试剂进行电解，电解产物为唯一的最终产物酯RC(O)OR'。