Synthesis of the C-1-C-28 ABCD unit of spongistatin 1.
The synthesis of the C-1-C-28 ABCD fragment of spongistatin is described. Anti-selective boron-mediated aldol coupling of a CD spiroketal ketone fragment to an AB spiroketal aldehyde unit forms the desired C1-C28 advanced intermediate. Other features include the double conjugate addition of a dithiol to an ynone to generate the key beta-keto-dithiane unit required for the synthesis of the AB spiroketal fragment. [reaction: see text]
Gaunt
Matthew J
MJ
Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, UK.
Jessiman
Alan S
AS
Orsini
Paolo
P
Tanner
Huw R
HR
Hook
David F
DF
Ley
Steven V
SV