Formal [4 + 2] benzannulation of 2-alkenyl indoles with aldehydes: a route to structurally diverse carbazoles and bis-carbazoles
作者:Ankush Banerjee、Avishek Guin、Shuvendu Saha、Anushree Mondal、Modhu Sudan Maji
DOI:10.1039/c8ob02875c
日期:——
Construction of structurally diverse carbazoles and bis-carbazoles by protecting-group-free formal [4 + 2]-benzannulation of 2-alkenyl indoles and aldehydes is demonstrated. The sequence of four different reactions is executed in one-pot using readily available and cheap bottle reagents as catalysts rendering this method attractive. The incorporation of inexpensive and environmentally benign molecular
Chemoselective room temperature E1cB N–N cleavage of oxazolidinone hydrazides from enantioselective aldehyde α-hydrazination: synthesis of (+)-1,4-dideoxyallonojirimycin
作者:Jasmin Ferreira、Sophie C. M. Rees-Jones、Valerie Ramaotsoa、Ath'enkosi Msutu、Roger Hunter
DOI:10.1039/c5ob02560e
日期:——
Room temperature E1cB N–N cleavage of oxazolidinone hydrazides via N-alkylation with diethyl bromomalonate and potassium or caesium carbonate as base in acetonitrile is presented. The new method has a much improved chemoselectivity, which is illustrated by a concise total synthesis of the piperidine iminosugar (+)-1,4-dideoxyallonojirimycin.
介绍了室温下的溴化丙二酸二乙酯和碳酸钾或碳酸铯在乙腈中的N-烷基化反应,从而使恶唑烷酮酰肼在室温下以E1cB N - N裂解。该新方法的化学选择性大大提高,哌啶亚氨基糖(+)-1,4-二脱氧烯隆吉利霉素的简明全合成说明了这一点。