The total synthesis of (±)-bulnesol and related studies
作者:J.A. Marshall、J.J. Partridge
DOI:10.1016/s0040-4020(01)82767-8
日期:1969.1
1,7-dimethylbicyclo[4.3.1]decan-10-ols 16e, 19e, and 79 and the subsequent rearrangement of their methanesulfonate derivatives to the corresponding hydroazulenes 22, 27, and 81 is described. The synthesis of the bicyclo[4.3.1]decane intermediates begins with 2-carbethoxycycloheptanones and proceeds via condensation with methyl vinyl ketone and cyclization of the resulting 2-carbethoxy-2-(3-oxobutyl)-cycloheptanones
A series of α-diazo carbonyl compounds tethered to cyclopentanone/cyclohexanone/1-tetralone units have been synthesized using a diazomethane solution to construct various fused cyclooctane ring systems via rhodium-generated carbonyl ylides. The reaction of rhodium(II) acetate dimer with various α-diazo carbonyl compounds generated transient cyclic seven-membered ring carbonyl ylides, which underwent facile 1,3-dipolar cycloadditions with dipolarophiles, like N-phenylmaleimide, p-benzoquinone, and DMAD to furnish a variety of fused epoxy-bridged cyclooctane ring systems in a tandem manner. Interestingly, an oxepine ring system was generated via an intramolecular proton transfer of a seven-membered ring carbonyl ylide. A tri-oxa polycyclic compound was obtained in the case of p-benzoquinone as dipolarophile. A single-crystal X-ray analysis of a fused cyclootanoid derivative is reported to decisively establish the structure and stereochemistry of the fused epoxy-bridged cyclooctane ring systems; a further analysis revealed the existence of a unique intermolecular C–H···π interaction motif in the solid-state architecture.