Ruthenium PNP pincer complexes bearing supplementary cyclometalated C,N-bound ligands have been prepared and fully characterized for the first time. By replacing CO and H- as ancillary ligands in such complexes, additional electronic and steric modifications of this topical class of catalysts are possible. The advantages of the new catalysts are demonstrated in the general α-alkylation of ketones with alcohols following a hydrogen autotransfer protocol. Herein, various aliphatic and benzylic alcohols were applied as green alkylating agents for ketones bearing aromatic, heteroaromatic or aliphatic substituents as well as cyclic ones. Mechanistic investigations revealed that during catalysis, Ru carboxylate complexes are predominantly formed whereas neither the PNP nor the CN ligand are released from the catalyst in significant amounts.

中文翻译：

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环金属化钌钳配合物作为酮与醇进行α-烷基化的催化剂。

带有辅助环金属化C，N键合配体的钌PNP钳形配合物已经制备并首次进行了全面表征。通过代替这种配合物中的CO和H-作为辅助配体，这种局部使用的催化剂可以进行额外的电子和空间修饰。遵循氢自动转移方案，酮与醇的一般α-烷基化反应证明了新型催化剂的优势。在此，将各种脂族和苄醇用作带有芳族，杂芳族或脂族取代基以及环状取代基的酮的绿色烷基化剂。机理研究表明，在催化过程中，主要形成Ru羧酸盐配合物，而PNP和CN配体均未从催化剂中大量释放。