Isocyclics startg

A soln. of startg. diyne and 1.5 eqs. benzaldehyde in THF treated with catalytic amounts of Ni(cod)2 and Bu3P at 135° for 5 h - product. Y 52%. The structure of the diyne (nature of terminal alkyl group and length of chain) has a marked effect on the course of reaction, vinyl- and en-isocyclics being isolated in certain cases. F.e.s. T. Tsuda et al., J. Am. Chem. Soc. 110, 8570-2 (1988). 

Startg. octalindione treated with 1 equivalent NaBH4 in ethanol to reduce the a,/ -satd. carbonyl, hydrogenated with Pd-on-charcoal in 3 1 ethyl acetate-triethylamine to eliminate the isocyclic double bond, the isoxazole ring hydro-genolyzed with Raney-Ni in ethanol, finally refluxed 7 hrs. with Og-free metha-nolic Na-methoxide then 15 hrs. with aq. 3%-NaOH -> tricyclic enone (startg. m. f. 837). Overall Y 60%. G. Stork and J. E. McMurry, Am. Soc. 89, 5461, 5459, 5463, 5464 (1967). 

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