Yashwant S. Kulkarni

Simple syntheses of (±) -β-copaene, (±) -β-ylangene and lemnalol.

Abstract The ketone 1a, which we have prepared from geranylacetone in 38% yield by a four step sequence, has been converted to β-copaene and β-ylangene by a three step sequence. Oxidation of β-ylangene with SeO 2 gives lemnalol in 76% yield.

Intramolecular [2 + 2] cycloaddition reactions of vinylketenes. stereo- and regiospecific preparation of vinylketenes from α,β-unsaturated acid chlorides.

Treatment of α,β-unsaturated acid chlorides 5, 6, 14, 17, and 18 with NEt3 in toluene at reflux generates, stereo- and regiospecifically, the vinylketene which undergoes a facile intramolecular [2 + 2] cycloaddition.