We synthesized or re-synthesized a large series of 2H-1,5-benzodioxepin-3(4H)-ones 9 (Scheme 1), 4,5-dihydro-1-benzoxepin-3(2H)-ones 10 (Schemes 3 and 4) and 5,6,8,9-tetrahydro-7H-benzocyclohepten-7-ones 11 (Schemes 5 and 6), since the lead compound for the olfactory note of perfumes based on marine accords is a well-known benzodioxepinone named Calone 1951 (9b). We meticulously described the odor profile of each synthesized compound and discussed relevant structure -odor relationships (Tables 1 -3). In particular, we revealed a correlation between the conformation of the seven-membered ring and the activities of these compounds (Table 4 and Fig. 3). We also clarified the effect of the position and the size of the alkyl substituent at the aromatic ring.

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~~ ~Pd(dbah[dba = dibenzylideneacetoneJ/PPh3-or Pd(PPh,)4-catalyzed cyclizations of acetoxy-dienes 2 + 3 and 10 + 11 gave 1-vinyl-2-methylidene-substituted cyclopentanes and cyclohexanes in high yield, consistent with a palladium-ene/p-elimination mechanism (D + E + F, Scheme 2). The efficient and highly stereoselective cyclizations 4 + 7 and 8 -+ 9 illustrate intramolecular allylpalladium insertions into 1,2-diaikyl-, trialkyl-, and cyclic alkenes followed by elimination of the exocyclic a-H giving 1,2-divinylcyclopentanes. These new olefin insertions proceed faster in AcOH (compared to THF) and occur preferentially cis relative to the Pd (13 -+ 14 -+ 15). Scheme 1In conjunction with our previous studies of the magnesium-ene cyclization [ 11 (Scheme I ) , we envisaged the extension of this concept to catalytic intramolecular palladium-ene reactions2) (Scheme 2).