Functionalized 4-Carboxy- and 4-Keto-2,3-dihydropyrroles via Ni(II)-Catalyzed Nucleophilic Amine Ring-Opening Cyclizations of Cyclopropanes
作者:M. Cynthia Martin、Dadasaheb V. Patil、Stefan France
DOI:10.1021/jo5001059
日期:2014.4.4
is reported using Ni(ClO4)2·6H2O as a Lewis acid catalyst for nucleophilic amine ring-opening cyclizations of donor–acceptor (D–A) cyclopropanes. This methodology provided good to excellent yields of functionalized 2,3-dihydropyrroles under milder reaction conditions than previously reported and is amenable to a variety of D–A cyclopropanes and primary amines.
An organocatalytic Cloke–Wilson rearrangement of cyclopropyl ketones to 2,3-dihydrofurans is exploited utilizing the homoconjugate addition process. With 1,4-diazabicyclo[2.2.2]octane as the catalyst, the rearrangement in DMSO at 120 °C proceeded in generally high yields, exclusive regioselectivity, and a broad substrate scope. An examination of the mechanism including stereochemical analysis and intermediate
[5C + 1N] Annulations: Two Novel Routes to Substituted Dihydrofuro[3,2-<i>c</i>]pyridines
作者:Peng Huang、Rui Zhang、Yongjiu Liang、Dewen Dong
DOI:10.1021/ol302314c
日期:2012.10.19
synthesis of 2,3-dihydrofuro[3,2-c]pyridines are described. Ammonium acetate (NH4OAc) is used as an ammonia source in both routes. The first route utilizes 1-acyl-1-[(dimethylamino)alkenoyl]cyclopropanes as a five-carbon 1,5-bielectrophilic species and combines the [5C + 1N] annulation and regioselective ring-enlargement of cyclopropylketone into one pot, whereas the second route utilizes 3-acyl-2-[(dim
描述了两种基于[5C + 1N]环合的新颖路线,用于合成2,3-二氢呋喃[3,2- c ]吡啶。两种途径均使用乙酸铵(NH 4 OAc)作为氨源。第一种方法利用1-酰基-1-[[(二甲基氨基)链烯酰基]环丙烷作为五碳1,5-双亲电子物质,并将环丙基酮的[5C + 1N]环合和区域选择性环扩大结合到一个罐中,而第二种方法利用3-酰基-2-[((二甲氨基)烯基] -4,5-二氢呋喃作为五碳合成子,其涉及顺序的分子间氮杂加成,分子内氮杂亲核加成/消除和脱水反应。
Danion-Bougot,R.; Carrie,R., Bulletin de la Societe Chimique de France, 1972, p. 3511 - 3520