TY - JOUR T1 - Metal-mediated alkynediol cycloisomerization: first and second generation formal total syntheses of didemniserinolipid B JF - Tetrahedron Y1 - 2013 A1 - Das, Shyamsundar A1 - Induvadana, Boddeti A1 - Ramana, C. V. KW - Alkynol-cycloisomerization KW - Bicyclic ketal KW - Gold catalysis KW - Palladium catalysis KW - Zipper reaction AB -

A formal total synthesis of didemniserinolipid B was developed by employing a regioselective metal-mediated 6-endo-dig alkynol-cycloisomerization reaction. Two routes for the synthesis of key Burke's intermediate have been developed. Our initial approach involved the introduction of a C-17-allcynol followed by Pd-mediated cycloisomerization and then coupling with the serinol unit prior to the introduction of an alpha,beta-unsaturated ester unit through selective oxidation of 1 degrees-OH followed by a two-carbon Wittig homologation. Alternatively, the second generation strategy featuring the serinol coupling with the C-17-alkynol followed by alkyne addition to the epoxide and subsequent Au-mediated cycloisomerization of an acetonide protected alkynediol unit has been executed. This approach has avoided several late stage protection-deprotection events. (C) 2012 Elsevier Ltd. All rights reserved.

PB - PERGAMON-ELSEVIER SCIENCE LTD CY - THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND VL - 69 IS - 7 U3 - Foreign U4 - 2.817 ER -