Approaches to the synthesis of cytochalasans. Part 7. Synthesis of some building blocks for the construction of the macrocyclic moiety

The synthesis of ethyl (2E, 4E, 8R)‐8‐methyl‐10‐[(2H‐tetrahydropyran‐2‐yl)oxy]‐2,4‐decadienoate (11), methyl (2E, 8R)‐8‐methyl‐10‐[(2H‐tetrahydropyran‐2‐yl)oxy]‐2‐decenoate (16), synthons for the construction of the macrocyclic moieties of the cytochalasins A, B and F, and of (3R)‐[7‐(1,3‐dioxolan‐2‐yl)‐3‐methylheptyl]triphenyl‐phosphonium bromide (24), a C8‐building block for deoxaphomin, proxiphomin and protophomin is described. In all instances (+)‐(R)‐pulegone (5) served as starting material.