Stereoselective Synthesis of Seven-Membered Carbocycles from 2-Amino-1,3-butadienes and Vinyl Chromium Fischer-Type Carbenes
摘要:
Seven-membered ring carbocycles are prepared by reaction of easily avaliable 2-amino-1,3-butadienes with vinyl Fischer carbenes. Hydrolysis of the cycloadduct initially formed gives rise to cyclohepta-1,3-diones with total regio- and stereoselectivity in a one-pot process. When 2-aminobutadienes bearing a prolinol derivative as a chiral auxiliary are used, the corresponding cyclic diketones are obtained with very high enantiomeric excesses. The absolute configuration of the stereogenic centers generated was determined with the aid of ROESY and CD measurements.
2-Amino-1,3-butadienes bearing commercially available S-(+)-2-(methoxymethyl)pyrrolidine as chiral auxiliary undergo a [4 + 2] cycloaddition reaction with nitroalkenes to furnish 4-nitrocyclohexanones upon hydrolysis of the resulting enamine. The cycloadducts are obtained with good yields and very high enantiomeric excesses. The reaction has been performed with aromatic and aliphatic conjugated nitroalkenes. Moreover, a 2-amino diene which features a (Z) double bond undergoes a Michael addition reaction with nitroalkenes, which gives rise to open chain compounds with high enantioselectivity. After acidic hydrolysis, the open chain compounds cyclize to form chiral substituted furans.
2-Amino-1,3-butadienes as chiral building blocks: enantioselective synthesis of 4-piperidones, 4-nitrocyclohexanones, and 1,3-cycloheptadione derivatives
作者:Jose Barluenga、Fernando Aznar、Carlos Valdes、Alfredo Martin、Santiago Garcia-Granda、Eduardo Martin
DOI:10.1021/ja00063a085
日期:1993.5
Barluenga, Jose; Aznar, Fernando; Ribas, Cristina, Chemistry - A European Journal, 1996, vol. 2, # 7, p. 805 - 811
Stereoselective Synthesis of Seven-Membered Carbocycles from 2-Amino-1,3-butadienes and Vinyl Chromium Fischer-Type Carbenes
作者:Jose Barluenga、Fernando Aznar、Alfredo Martin、Jesus T. Vazquez
DOI:10.1021/ja00142a006
日期:1995.9
Seven-membered ring carbocycles are prepared by reaction of easily avaliable 2-amino-1,3-butadienes with vinyl Fischer carbenes. Hydrolysis of the cycloadduct initially formed gives rise to cyclohepta-1,3-diones with total regio- and stereoselectivity in a one-pot process. When 2-aminobutadienes bearing a prolinol derivative as a chiral auxiliary are used, the corresponding cyclic diketones are obtained with very high enantiomeric excesses. The absolute configuration of the stereogenic centers generated was determined with the aid of ROESY and CD measurements.