Hexafluoroisopropanol Promoted Ring‐Opening‐Cyclization of Donor–Acceptor Cyclopropanes with Primary Amines
摘要:
We reveal here a catalyst‐free, ring‐opening‐cyclization of donor‐acceptor cyclopropanes with primary amines to synthesize functionalized dihydropyrroles. This protocol avoids inert conditions and solvents promoted by hexafluoroisopropanol (HFIP). The reaction is quite general with aryl, alkyl, and alicyclic amines. A good number of cyclopropanes bearing keto groups reacted excellently to produce the desired products. Further, we complemented this method with Meldrum's acid‐derived cyclopropanes for synthesizing γ‐lactams. We have demonstrated the post‐synthetic applications of the products and gram‐scale synthesis to highlight the adaptability of this synthetic protocol.
Hexafluoroisopropanol Promoted Ring‐Opening‐Cyclization of Donor–Acceptor Cyclopropanes with Primary Amines
摘要:
We reveal here a catalyst‐free, ring‐opening‐cyclization of donor‐acceptor cyclopropanes with primary amines to synthesize functionalized dihydropyrroles. This protocol avoids inert conditions and solvents promoted by hexafluoroisopropanol (HFIP). The reaction is quite general with aryl, alkyl, and alicyclic amines. A good number of cyclopropanes bearing keto groups reacted excellently to produce the desired products. Further, we complemented this method with Meldrum's acid‐derived cyclopropanes for synthesizing γ‐lactams. We have demonstrated the post‐synthetic applications of the products and gram‐scale synthesis to highlight the adaptability of this synthetic protocol.
Direct Electrophilic C−H Alkynylation of Unprotected 2-Vinylanilines
作者:Lucien D. Caspers、Peter Finkbeiner、Boris J. Nachtsheim
DOI:10.1002/chem.201606026
日期:2017.2.24
Unprotected aromatic amines can be used as directing groups in metal‐catalyzed C−H alkynylations of alkenes. By using low amounts of an IrIII catalyst in combination with alkynylbenziodoxolones as electrophilic alkyne‐transfer reagents, highly desirable 1,3‐enynes were isolated in excellent yields of up to 98 % with Z stereoselectivity. A broad substrate scope as well as the high synthetic utility