Synthesis of C1-C13 Segment of Poecillastrin C

A stereoselective synthesis of C1-C13 segment of poecillastrin C has been achieved. C1-C4 moiety was derived from diallyl tartrate, and the amide group at C3 position was constructed by traceless Staudinger reaction. The C1-C13 segment was submitted to model studies including esterification with bulky alcohol at C1 position and the Stille coupling with vinyl iodide at C13 position. The reactivity of C1 position was affected by the neighboring C2-protective group. When the C2 hydroxy group was protected as TBS ether, the C1 carboxylic acid did not undergo esterification with a bulky secondary alcohol, while the p-methoxybenzylidene N,O-acetal afforded 2,4-dimethyl-3-pentyl ester. The Stille coupling of C1-C13 segment with 1-iodo-1-heptene gave the southern part of poecillastrin C macrolactam attaching with simplified east and west parts.