A visible-light-mediated process for dehydrogenation of amines has been described. The given protocol showed a broad substrate scope, mild reaction conditions and excellent results without the requirement of tedious purification. This process can be applied in one-pot functionalization of secondary amines with various nucleophiles through the cooperation of visible-light and Lewis acid catalysis, leading
Syntheses of Optically Active Tetrahydro-1<i>H</i>-pyrrolo[1,2-<i>a</i>]imidazol-2-ones and Hexahydroimidazo[1,2-<i>a</i>]pyridin-2(3<i>H</i>)-ones
作者:Alan R. Katritzky、Hai-Ying He、Jing Wang
DOI:10.1021/jo010842w
日期:2002.7.1
The reactions of (2S)-2-amino-2-substituted-N-(4-nitrophenyl)acetamides 16a-c, succindialdehyde (13), and benzotriazole afforded enantiopure (3S,5R,7aR)-5-(1H-1,2,3-benzotriazol-1-yl)-3-substituted1-(4-nitrophenyl)tetrahydro-1H-pyrrolo[1,2-a]imidazol-2-ones 17a-c, which were converted by sodium borohydride into (3S,7aR)-3-substituted-1-(4-nitrophenyl)tetrahydro-1H-pyrrolo[1,2-a]imidazol-2-ones 18a-c. Chiral (2S)-2-amino-2-substituted-N-(4-methylphenyl)acetamides 12a-d, easily prepared in two steps from N-Boc-alpha-amino acids 10a-d, similarly reacted with glutaraldehyde (20) and benzotriazole to generate 5-benzotriazolyl-3-substituted-hexahydroimidazo[1,2-a]pyridin2(3H)-ones 21a-d, which were converted by sodium borohydride directly into optically active 3-substituted-hexahydroimidazo[1,2-a]pyridin-2(3H)-ones 22a-d.
Stereoselective syntheses of chiral (3S,9bS)-1,2,3,9b-tetrahydro-5H-imidazo[2,1-a]isoindol-5-ones
作者:Alan R. Katritzky、Hai-Ying He、Akhilesh K. Verma
DOI:10.1016/s0957-4166(02)00220-3
日期:2002.6
Chiral (3S,9bS)-1,2,3,9b-tetrahydro-5H-imidazo[2,1-a]isoindol-5-ones 11a-11f, 14b.14c and 17a,b were prepared in 78-93% yields with high stereoselectivities (d.e. >99%) by the intermolecular condensations of 2-formylbenzoic acids 10 or 13 or 2-acetylbenzoic acid 15 with chiral diamines 9a-9f and 9h. Compounds 9a-9f and 9h were readily prepared in three steps from optically active N-Boc-alpha-amino acids 5a-5d. (C) 2002 Elsevier Science Ltd. All rights reserved.