Amides as precursors of imidoyl radicals in cyclisation reactions
作者:W. Russell Bowman、Anthony J. Fletcher、Jan M. Pedersen、Peter J. Lovell、Mark R.J. Elsegood、Elena Hernández López、Vickie McKee、Graeme B.S. Potts
DOI:10.1016/j.tet.2006.10.030
日期:2007.1
Amides have been successfully used as precursors of imidoyl radicals for radical cyclisation. The amides have been converted to imidoyl selanides via reaction with phosgene to yield imidoyl chlorides followed by reaction with potassium phenylselanide. Imidoyl selanides were reacted with tributyltin hydride (Bu3SnH) as the radical mediator with triethylborane or AIBN as initiators to yield imidoyl radicals
Described herein is a continuous‐flow strategy for the palladium‐catalyzed direct C−H arylation of indole‐3‐acetic acid derivatives with arenediazonium salts. A fully autonomous self‐optimizing flow platform was used to efficiently optimize the coupling reaction in a three‐dimensional space. The flow methodology developed is experimentally simple, mild, broad in scope, and safer than traditional batch
N-Heterocyclic-Carbene-Catalyzed Umpolung of Imines
作者:Atanu Patra、Subrata Mukherjee、Tamal Kanti Das、Shailja Jain、Rajesh G. Gonnade、Akkattu T. Biju
DOI:10.1002/anie.201611268
日期:2017.3.1
N‐Heterocycliccarbene (NHC) catalysis has been widely used for the umpolung of aldehydes, and recently for the umpolung of Michael acceptors. Described herein is the umpolung of aldimines catalyzed by NHCs, and the reaction likely proceeds via aza‐Breslow intermediates. The NHC‐catalyzed intramolecular cyclization of aldimines bearing a Michael acceptor resulted in the formation of biologically important
Imidoyl radicals, generated from imidoyl phenylselanide precursors, have been used for the synthesis of 2,3-disubstitutedindoles. A facile high yielding synthesis of imidoyl phenylselanides has been developed. The potential for neophyl rearrangement of 5-exo radical intermediates to 6-endo radical intermediates is discussed.