A new approach to the synthesis of 3,4-dihydroisocoumarin derivatives
摘要:
A new, simple, one-step synthesis of 3-substituted 3,4-dihydroisocoumarins is developed. The products are obtained by the reaction of o-methoxycarbonyl arenediazonium bromides with unsaturated compounds in the presence of CuBr as a catalyst. (C) 2009 Elsevier Ltd. All rights reserved.
Practical Pd(II)-Catalyzed C–H Alkylation with Epoxides: One-Step Syntheses of 3,4-Dihydroisocoumarins
作者:Guolin Cheng、Tuan-Jie Li、Jin-Quan Yu
DOI:10.1021/jacs.5b07507
日期:2015.9.2
Pd(II)-catalyzed ortho-alkylation of benzoic acids with both terminal and internal epoxides affords 3,4-dihydroisocoumarins in one step. The presence of potassium countercations is crucial for this reaction. Monoprotected amino acid ligands significantly promote this reaction, enabling the development of a practical C-H alkylation reaction using 0.5 mol % Pd catalyst. The inversion of stereochemistry in the C-H alkylation step is consistent with a redox-neutral S(N)2 nucleophilic ring-opening process as opposed to a Pd(II)/Pd(IV) pathway.