First Total Synthesis of the 4<i>a</i>-Methyltetrahydrofluorene Diterpenoids (±)-Dichroanal B and (±)-Dichroanone
作者:Mainak Banerjee、Ranjan Mukhopadhyay、Basudeb Achari、Asish Kr. Banerjee
DOI:10.1021/ol035506b
日期:2003.10.1
[reaction: see text] A simple synthesis of the 4a-methyltetrahydrofluorene diterpenoids (+/-)-dichroanal B and (+/-)-dichroanone has been achieved through a common hexahydrofluorenoneintermediate obtained via Pd(0)-catalyzed reductive cyclization of a substituted 2-(2-bromobenzyl) methylene cyclohexane.
Intramolecular Heck reaction strategy for the synthesis of functionalised tetrahydroanthracenes: a facile formal total synthesis of the linear abietane diterpene, umbrosone
作者:Sujaya Sengupta、Ranjan Mukhopadhyay、Basudeb Achari、Asish Kr. Banerjee
DOI:10.1016/j.tetlet.2005.01.021
日期:2005.2
Rapid annulation employing an intramolecular Heck reaction yielded the functionalised 1,1,10-trimethyl-6-methoxy-1,2,3,4-tetrahydroanthracene 4a, a key intermediate for the linear diterpenoid quinone umbrosone (1), and the related compounds 4b-d. A similar strategy was also successfully adopted for the synthesis of the 9-methyl tetrahydroanthracene ester 5 and the tetrahydrodibenzo[a,d]cycloheptene ester 6. (C) 2005 Elsevier Ltd. All rights reserved.