Controlled Rearrangement of Lactam-Tethered Allenols with Brominating Reagents: A Combined Experimental and Theoretical Study on α- versus β-Keto Lactam Formation
作者:Benito Alcaide、Pedro Almendros、Amparo Luna、Sara Cembellín、Manuel Arnó、Luis R. Domingo
DOI:10.1002/chem.201101160
日期:2011.10.4
expansion of lactam‐tethered allenols to efficiently afford cyclic α‐ or β‐ketoamides with good yields and high chemo‐, regio‐, and diastereoselectivity, through controlled CC bond cleavage of the β‐ or γ‐lactam nucleus. Interestingly, in contrast to the rearrangement reactions of 2‐azetidinone‐tethered allenols, which lead to the corresponding tetramic acid derivatives (β‐keto lactam adducts) as the
Ñ溴代琥珀酰亚胺(NBS)顺利促进内酰胺拴allenols的环扩展以有效地得到环状α-或β酮酰胺具有良好的产率和高的化学-选择性,区域选择性和非对映选择性,通过控制Ç 的β的C键裂解γ或γ-内酰胺核。有趣的是,与2-氮杂环丁酮-系留的烯丙醇的重排反应形成唯一的产物相应的四酸衍生物(β-酮内酰胺加合物)相反,在相似条件下2-吲哚酮-系留的烯丙醇的反应产生了喹啉。 -2,3-二酮(α-酮内酰胺加成物)作为独家产品或主要产品。为了使实验观察合理化,已经进行了理论研究。