Synthesis of 7a-Substituted Hajos−Wiechert Ketone Analogues
作者:Jason W. J. Kennedy、Sophia Vietrich、Hilmar Weinmann、Dominic E. A. Brittain
DOI:10.1021/jo800638s
日期:2008.7.1
A general and efficient route to 2-substituted 1,3-cyclopentadiones 3 has been developed. This operationally simple, two-step procedure is amenable to mulfigram scale preparations of these useful synthetic intermediates. These compounds are then transformed to previously unknown, higher analogues of the Hajos-Parrish-Eder-Sauer-Wiechert ketone (enone 1, R = Me) following an enantioselective Robinson annulation.
Direct amino acid-catalyzed cascade biomimetic reductive alkylations: application to the asymmetric synthesis of Hajos–Parrish ketone analogues
作者:Dhevalapally B. Ramachary、Mamillapalli Kishor
DOI:10.1039/b807999d
日期:——
and enantioselective process for the double cascade synthesis of highly substituted 2-alkyl-cyclopentane-1,3-diones, 2-alkyl-3-methoxy-cyclopent-2-enones and Hajos-Parrish (H-P) ketone analogs is presented via reductive alkylation chemistry. For the first time, we have developed a single-step alkylation of cyclopentane-1,3-dione with aldehydes/ketones and a Hantzsch ester through an organocatalytic reductive