Synthesis of anti-tumour phosphatidylinositol analogues from glucose by the use of ring-closing olefin metathesis

A divergent strategy is described for synthesis of the novel phosphatidylinositols 1-3. The synthetic approach commences from benzyl-protected methyl 6-iodo-6-deoxy-a-D-glucopyranoside, which undergoes zinc-mediated reductive fragmentation followed by vinyl Grignard addition and ring-closing metathesis to afford the key conduritol B intermediate 7. This can trifurcate to form three different benzyl-protected myo-inositol headgroups 4-6, which after phosphorylation and attachment of the glycerolipid part give phosphatidylinositols 1-3. Preliminary biological testing against human colon adenocarcinoma cells reveals that analogues 1-3 are significant anti-tumour agents.