Conformational Control in the Rebeccamycin Class of Indolocarbazole Glycosides
摘要:
Indolocarbazole glycosides are balanced between two conformations: a "closed" conformation containing a cyclic hydrogen bond between the indolocarbazole NH and the pyranose oxygen and an "open" conformation in which the indolocarbazole NH is hydrogen bonded to solvent. The open conformation never has a commanding advantage, even in DMSO, but in nonpolar environments the cyclic conformation predominates.
Conformational Control in the Rebeccamycin Class of Indolocarbazole Glycosides
摘要:
Indolocarbazole glycosides are balanced between two conformations: a "closed" conformation containing a cyclic hydrogen bond between the indolocarbazole NH and the pyranose oxygen and an "open" conformation in which the indolocarbazole NH is hydrogen bonded to solvent. The open conformation never has a commanding advantage, even in DMSO, but in nonpolar environments the cyclic conformation predominates.
Enantioselective Palladium-Catalyzed Carbene Insertion into the N−H Bonds of Aromatic Heterocycles
作者:Vanessa Arredondo、Stanley C. Hiew、Eugene S. Gutman、Ilandari Dewage Udara Anulal Premachandra、David L. Van Vranken
DOI:10.1002/anie.201611845
日期:2017.4.3
C3‐substituted indoles and carbazoles react with α‐aryl‐α‐diazoesters underpalladiumcatalysis to form α‐(N‐indolyl)‐α‐arylesters and α‐(N‐carbazolyl)‐α‐arylesters. The products result from insertion of a palladium‐carbene ligand into the N−H bond of the aromatic N‐heterocycles. Enantioselection was achieved using a chiral bis(oxazoline) ligand, in many cases with high enantioselectivity (up to 99 %