The synthesis of an enantiopure building-block with a contiguous all-cis-trimethyldecalin motif embedded in unusual terpenes is described. Starting from the Wieland-Miescher ketone, the key step is a one-pot hydroboration of an exocyclic methylene double bond promoted by disiamylborane and radical-mediated protonolysis of the corresponding alkylborane using 4-tert-butylcatechol. (C) 2014 Elsevier Ltd. All rights reserved.
Carbon atom insertion bicycloannulation: total syntheses of ishwarane and ishwarone
作者:Robert M. Cory、Lester P. J. Burton、Dominic M. T. Chan、Fred R. McLaren、Mary H. Rastall、Richard M. Renneboog
DOI:10.1139/v84-328
日期:1984.10.1
methyllithium at low temperatures. This new bicycloannulation method has been employed in a totalsynthesis of ishwarane (1), the naturally occurring parent hydrocarbon of the ishwarane class of tetracyclic sesquiterpenes. Although this reaction was not successful with various possible precursors of ishwarone (2), this natural product was prepared in low yield by a two-step version of the carbon atom