The first synthesis of the title compound is described. The synthesis features an acetal-vinylsilane cyclization to stereoselectively form the cis-2,7-disubstituted oxepene ring and introduce Delta(4) unsaturation. Starting with (2R,3S)-2,3-epoxypentan-1-ol (16), mixed acetal 10 is formed in five steps and 72% overall yield. Treatment of 10 with excess BCl3 in CH2Cl2 at -78 --> 0 degrees C promotes cyclization to afford Delta(4)-oxepene 39 in 90% yield after deprotection of the silyl ether. Elaboration of the (E)-enyne functionality of the six-carbon side chain completes the synthesis of (+)-isolaurepinnacin.