A conceptually new total synthesis of oestrone, based on a novel cascade of radical cyclisations from the iodo aryl vinylcyclopropane 2, via 10, 15, 16 and 17, leading to the intermediate trans, anti,trans-oestradiol derivative 11 in one step, is described. Oxidation of 11, followed by dernethylation of the resulting aryl methyl ether 18 then gives (+/-)-oestrone 1. (C) 2004 Elsevier Ltd. All rights reserved.
A conceptually new total synthesis of oestrone, based on a novel cascade of radical cyclisations from the iodo aryl vinylcyclopropane 2, via 10, 15, 16 and 17, leading to the intermediate trans, anti,trans-oestradiol derivative 11 in one step, is described. Oxidation of 11, followed by dernethylation of the resulting aryl methyl ether 18 then gives (+/-)-oestrone 1. (C) 2004 Elsevier Ltd. All rights reserved.
A synthetic approach to ring-D aromatic steroids, viz. 5, based on a cascade of radical-mediated cyclisations from the orthoaryl-substituted iododienynones 12 and 13, instead led to the macrocyclic ketone 16 or to the novel, bridged tricycle 17, respectively, as the major products.
Cascade radical-mediated cyclisations with conjugated ynone electrophores. An approach to the synthesis of steroids and other novel ring-fused polycyclic carbocycles
作者:Gerald Pattenden、Davey A. Stoker、Nicholas M. Thomson
DOI:10.1039/b703373g
日期:——
A cascade radical-mediated Diels-Alder reaction with the iododienynone 16b produced the tricyclic ketone 17 (22%). By contrast, treatment of the substituted furans 36 and 47 with Bu(3)SnH-AIBN, instead led to the tetracycles 44 and 58 respectively, rather than the anticipated oestranes, i.e. 38 and 48. In a separate study, attempted cascade radical-mediatedcyclisations from the ortho-aryl substituted