Cobalt-Catalyzed Intramolecular C−H Amination with Arylsulfonyl Azides
作者:Joshua V. Ruppel、Rajesh M. Kamble、X. Peter Zhang
DOI:10.1021/ol702265h
日期:2007.11.1
C-H amination with arylsulfonylazides. The cobalt-catalyzed process can proceed efficiently under mild and neutral conditions in low catalyst loading without the need of other reagents or additives, generating nitrogen gas as the only byproduct. The catalytic system can be applied to primary, secondary, and tertiary C-H bonds and is suitable for a broad range of arylsulfonylazides, leading to high-yielding
Cobalt (II) complexes of porphyrins are effective catalysts for intramolecular nitrene insertion of C—H bonds with arylsulfonyl azides. The cobalt-catalyzed process can proceed efficiently under mild and neutral conditions in low catalyst loading without the need of other reagents or additives, generating nitrogen gas as the only byproduct. Using the simple tetraphenylporphyrin (TPP) as the ligand, the cobalt-catalyzed intramolecular amidation can be applied to primary, secondary, and tertiary C—H bonds and suitable for a broad range of arylsulfonyl azides, leading to the syntheses of various benzosultam derivatives in excellent yields
'Salen' along: The iridium(III)–salen complex 1 efficiently catalyzes the title reaction of 2‐ethylbenzenesulfonyl azides to give five‐membered sultams with high enantioselectivity. Other 2‐alkyl‐substitued substrates lead to five‐ and six‐membered sultams with high enantioselectivity; the regioselectivity depends upon the substrate and the catalyst used. EDG=electron‐donating group.