Enantioselective Decarboxylative Alkylation Reactions: Catalyst Development, Substrate Scope, and Mechanistic Studies
作者:Douglas C. Behenna、Justin T. Mohr、Nathaniel H. Sherden、Smaranda C. Marinescu、Andrew M. Harned、Kousuke Tani、Masaki Seto、Sandy Ma、Zoltán Novák、Michael R. Krout、Ryan M. McFadden、Jennifer L. Roizen、John A. Enquist、David E. White、Samantha R. Levine、Krastina V. Petrova、Akihiko Iwashita、Scott C. Virgil、Brian M. Stoltz
DOI:10.1002/chem.201003383
日期:2011.12.9
functions with nearly identical efficiency in terms of yield and enantioselectivity. Catalyst discovery and development, the optimization of reaction conditions, the exploration of reaction scope, and applications in target‐directed synthesis are reported. Experimental observations suggest that these alkylation reactions occur through an unusual inner‐sphere mechanism involving binding of the prochiral
在钯配合物与各种膦恶唑啉 (PHOX) 配体的存在下,通过不稳定的前手性烯醇化亲核试剂对烯丙基和炔丙基亲电子试剂进行新颖的对映选择性烷基化来获得 α-季酮。三类烯醇化物前体获得了优异的产率和高对映体过量:烯醇碳酸酯、烯醇硅烷和外消旋 β-酮酯。这些底物类别中的每一种在产率和对映选择性方面都具有几乎相同的效率。报道了催化剂的发现和开发、反应条件的优化、反应范围的探索以及在靶向合成中的应用。实验观察表明,这些烷基化反应通过一种不寻常的内球机制发生,涉及前手性烯醇化亲核试剂直接与钯中心结合。