Organometallic Chemistry sans Organometallic Reagents: Modulated Electron‐Transfer Reactions of Subvalent Early Transition Metal Salts
作者:John J. Eisch、Xian Shi、Joseph R. Alila、Sven Thiele
DOI:10.1002/cber.19971300903
日期:1997.9
reductant, titanium dichloride, has been throughly examined, as well as the analogous ZrCl2 and HfCl2 reagents, all of which are readily obtainable by the alkylative reduction of the Group tetrachloride by butyllithium in THF. Noteworthy is that such interactions of MCl4 with butyllithium in hydrocarbon media lead, in contrast, to M(III) or M(IV) halide hydrides. Analogous alkylative reductions in THF
低价,早期过渡金属试剂在有机化学中作为选择性还原剂的潜力已通过对McMurry反应及其众多变体中产生的不明确且不均一的亚价钛中间体的深入研究而得以预示。作为开发对有机底物具有调制和选择性活性的可溶,定义明确的过渡金属还原剂的长期研究工作的一部分,已彻底检查了可溶于THF的还原剂二氯化钛以及类似的ZrCl 2和HfCl 2试剂,通过在THF中用丁基锂对四氯化物进行烷基化还原,很容易获得所有这些试剂。值得注意的是,MCl 4的这种相互作用相反,在烃介质中用丁基锂制得的M(III)或M(IV)卤化物氢化物。应用于VCl 4,CrCl 3和MoCl 5的THF中类似的烷基化还原反应产生的还原剂与从Mcl 4获得的还原剂相似,但反应活性分级。已证明这种还原剂能够以与涉及两电子转移(TET)的氧化加成一致的方式偶联羰基衍生物,苄基卤化物,乙炔和某些烯烃。这种反应途径与观察到的由酮形成频哪醇的立体化学以及炔烃的还原性二聚化相一致。与CrCl