Development of a New and Practical Route to Chiral 3,4-Disubstituted Cyclopentanones: Asymmetric Alkylation and Intramolecular Cyclopropanation as Key C−C Bond-Forming Steps
摘要:
An efficient and practical asymmetric synthesis of (+)-trans-3-hydroxymethyl-4-(3-fluorophenyl)cyclopentanone (1) is described. An asymmetric Mo-catalyzed alkylation reaction was used to establish the first stereocenter and a Cu-catalyzed intramolecular diastereoselective cyclopropanation reaction was used to set the second stereocenter. The last step involved a one-pot ring-opening/deprotection/hydrolysis/decarboxylation sequence that furnished the desired product in good yield.
Molybdenum-catalyzedasymmetricallylicalkylationreactions were carried out using the inexpensive, air-stable, and readily available Mo(CO)6 as precatalyst. In situ IR was used to determine the required activation time and temperature required to achieve the maximum concentration of the ‘‘active’’ catalyst from the molybdenum-precatalyst and chiral ligand. Results from comparison studies are consistent
Development of a New and Practical Route to Chiral 3,4-Disubstituted Cyclopentanones: Asymmetric Alkylation and Intramolecular Cyclopropanation as Key C−C Bond-Forming Steps
作者:Michael Palucki、Joann M. Um、Nobuyoshi Yasuda、David A. Conlon、Fuh-Rong Tsay、Frederick W. Hartner、Yi Hsiao、Benjamin Marcune、Sandor Karady、David L. Hughes、Peter G. Dormer、Paul J. Reider
DOI:10.1021/jo025890a
日期:2002.8.1
An efficient and practical asymmetric synthesis of (+)-trans-3-hydroxymethyl-4-(3-fluorophenyl)cyclopentanone (1) is described. An asymmetric Mo-catalyzed alkylation reaction was used to establish the first stereocenter and a Cu-catalyzed intramolecular diastereoselective cyclopropanation reaction was used to set the second stereocenter. The last step involved a one-pot ring-opening/deprotection/hydrolysis/decarboxylation sequence that furnished the desired product in good yield.