enantioselective formal [4+2] cycloadditions of 3‐nitroindoles are presented. By using 3‐nitroindoles in combination with an organocatalyst, chiral dihydrocarbazole scaffolds are formed in moderate to good yields (up to 87 %) and enantioselectivities (up to 97 % ee). The reaction was extended to include enantioselective [4+2] cycloadditions of 3‐nitrobenzothiophene. The reaction proceeds through a [4+2] cycl
Chemoselective N-Acylation of Indoles and Oxazolidinones with Carbonylazoles
作者:Stephen T. Heller、Erica E. Schultz、Richmond Sarpong
DOI:10.1002/anie.201203976
日期:2012.8.13
Unique reactivity: In the presence of more reactive amine and alcohol functional groups and of carboxylic acids, the chemoselective N‐acylation of indoles (see scheme) and oxazolidinones is achieved by taking advantage of the unique reactivity of carbonylazole acylating agents with catalytic amounts of 1,8‐diazabicyclo[5.4.0]undec‐7‐ene (DBU).