Intramolecular Heck cyclization of α-sulfenyl enol triflates. Asymmetric synthesis of a pentacyclic cardenolide precursor having functionality at C-11
摘要:
A concise route to the core of complex cardenolides is described. The sequence features use of a sulfone to join enantioenriched A and D ring fragments and also control intramolecular aldolization to generate ring C and an intramolecular Heck cyclization of an alpha-sulfenyl enol triflate to form the steroid skeleton. (C) 1998 Elsevier Science Ltd. All rights reserved.
Intramolecular Heck cyclization of α-sulfenyl enol triflates. Asymmetric synthesis of a pentacyclic cardenolide precursor having functionality at C-11
摘要:
A concise route to the core of complex cardenolides is described. The sequence features use of a sulfone to join enantioenriched A and D ring fragments and also control intramolecular aldolization to generate ring C and an intramolecular Heck cyclization of an alpha-sulfenyl enol triflate to form the steroid skeleton. (C) 1998 Elsevier Science Ltd. All rights reserved.