A synthesis of the prelog-djerassi lactone using open-chain stereocontrol based on allylsilane chemistry
作者:Hak-Fun Chow、Ian Fleming
DOI:10.1016/s0040-4039(01)80827-3
日期:——
A stereocontrolled synthesis of the Prelog-Djerassilactone (28) is described; all the stereocontrol stems from the high diastereoselectivity of electrophilic attack on a double bond adjacent to a chiral centre carrying a silyl group.
The (7R,15R)- and (7S,15R)-diastereomers of dolatrienoic acid were synthesized using a convergent strategy. Fragment C5-C9 was obtained through enantiodifferentiation of racemic pentane-1,3,5-triol as the key step, fixing the chirality at C7 of fragments 4 and ent-4. The chirality at C15 of the fragment C10-C16 was introduced from L-glutamic acid. Coupling of these two fragments led to the aldehydes (7R,15R)- and (7S,15R)-2 which were homologated by Horner-Wadsworth-Emmons condensation to give (7R,15R)- and (7S,15R)-dolatrienoic acids.