向羰基化合物中添加有机金属试剂已成为通过碳-碳键形成合成叔醇和仲醇的通用方法。然而,由于缺乏良好的亲核性或存在有机金属试剂的强碱性,由酮有效地合成叔醇特别困难并且因此受到限制。我们最近使用ZnCl 2,Me 3 SiCH 2开发了格氏试剂(RMgX:R =烷基,芳基; X = Cl,Br,I),对酮进行了高效的催化烷基化和芳基化反应MgCl和LiCl,可有效减少有问题的副反应。原则上,对于加成羰基化合物,RMgBr和RMgI的反应性不如RMgCl。因此,这种新颖的方法与均相催化的ZnCl 2 ·我3 SICH 2 MgCl·LiCl是相当有吸引力的,因为RMgBr和RMGI,其易于制备和/或可商购的,如RMgCl,可以成功地应用。除酮和醛以外,醛亚胺也有效地用于该催化反应,并以高收率获得了相应的仲胺。关于β-甲硅烷基效应和盐效应的机理细节,原位制备[R(Me 3 SiCH 2)2 Zn] -
The addition of organometallic reagents to carbonyl compounds has become a versatile method for synthesizing tertiary and secondary alcohols via carbon−carbon bond formation. However, due to the lack of good nucleophilicity or the presence of strong basicity of organometallic reagents, the efficientsynthesis of tertiary alcohols from ketones has been particularly difficult and, thus, limited. We recently
向羰基化合物中添加有机金属试剂已成为通过碳-碳键形成合成叔醇和仲醇的通用方法。然而,由于缺乏良好的亲核性或存在有机金属试剂的强碱性,由酮有效地合成叔醇特别困难并且因此受到限制。我们最近使用ZnCl 2,Me 3 SiCH 2开发了格氏试剂(RMgX:R =烷基,芳基; X = Cl,Br,I),对酮进行了高效的催化烷基化和芳基化反应MgCl和LiCl,可有效减少有问题的副反应。原则上,对于加成羰基化合物,RMgBr和RMgI的反应性不如RMgCl。因此,这种新颖的方法与均相催化的ZnCl 2 ·我3 SICH 2 MgCl·LiCl是相当有吸引力的,因为RMgBr和RMGI,其易于制备和/或可商购的,如RMgCl,可以成功地应用。除酮和醛以外,醛亚胺也有效地用于该催化反应,并以高收率获得了相应的仲胺。关于β-甲硅烷基效应和盐效应的机理细节,原位制备[R(Me 3 SiCH 2)2 Zn] -
Highly Efficient Alkylation to Ketones and Aldimines with Grignard Reagents Catalyzed by Zinc(II) Chloride
作者:Manabu Hatano、Shinji Suzuki、Kazuaki Ishihara
DOI:10.1021/ja0628405
日期:2006.8.1
efficient alkylation to ketones and aldimines with Grignardreagents in the presence of catalytic trialkylzinc(II) ate complexes derived from ZnCl2 (10 mol %) in situ was developed. This simple Zn(II)-catalyzed alkylation could minimize the well-known but serious problems with the use of only Grignardreagents, which leads to reduction and aldol side products, and the yield of desired alkylation products
在由 ZnCl2 (10 mol%) 衍生的催化三烷基锌 (II) 酸酯配合物的存在下,使用格氏试剂高效地烷基化为酮和醛亚胺。这种简单的 Zn(II) 催化烷基化可以最大限度地减少仅使用格氏试剂而导致还原和羟醛副产物的众所周知但严重的问题,并且可以提高所需烷基化产物的产率。
Zinc(ii)-catalyzed Grignard additions to ketones with RMgBr and RMgI
Highly efficient alkylations and arylations of ketones with Grignard reagents (RMgBr and RMgI) have been developed using catalytic ZnCl(2), Me(3)SiCH(2)MgCl, and LiCl. Tertiary alcohols were obtained in high yields with high chemoselectivities, while minimizing undesired side products produced by reduction and enolization.