Iron(III) Chloride/Phenylsilane‐Mediated Cascade Reaction of Allyl Alcohols with Maleimides: Synthesis of Poly‐Substituted γ‐Butyrolactones
作者:Hua Zhang、Xiao‐Yu Zhan、Xu‐Ling Chen、Lei Tang、Shuai He、Zhi‐Chuan Shi、Yu Wang、Ji‐Yu Wang
DOI:10.1002/adsc.201900843
日期:2019.11.5
A iron‐catalyzed free radical cascade reaction of allyl alcohols with N‐substituted maleimides for accessing poly‐substituted γ‐butyrolactones has been developed. In this protocol, various allyl alcohols can open N‐substituted maleimide rings to form allyl ester intermediates, and the allyl ester intermediates can be converted into an allyl ester alkyl radicals and undergo intramolecular free radical
formations between allyl carbonates and nontoxic allyl, allenyl, or propargyl boronates. This report represents the first use of these types of boronicesters in this particular context. The present transformations proceeded with high selectivity under remarkably mild conditions, and various functional groups including an aldehyde function proved to be compatible. In addition, several boronates were found
Rhodium-Catalyzed Synthesis of γ-Pyrones by Three Consecutive Redox-Aldol Reactions of Allylic Alcohols with α,β-Unsaturated Aldehydes
作者:Akio Mizuno、Hiroyuki Kusama、Nobuharu Iwasawa
DOI:10.1002/chem.201001068
日期:——
All together now! A unique RhI‐catalyzed reaction was developed to produce γ‐pyrones, which are 1,3,5‐triketone equivalents. This reaction was thought to proceed by three redox reactions of allylicalcohols, two intermolecular aldol reactions of α,β‐unsaturated aldehydes, and one intramolecular aldol reaction to afford 1,3‐cyclohexanediones, which were then converted into γ‐pyrones (see scheme; TMSOTf=trimethylsilyl