Ethylene derivatives oxetane ring

A 10-20%-soln. of the startg. m. (mixture of cis- and rrawj-isomers) in diphenyl-methane heated at 280-300° in a Pyrex ampoule methyl 3-methyl-2-butenoate. Y 90%.-In combination with photochemical oxetane ring synthesis from ethylene derivs. and oxo compds. (s. Synth. Meth. 19, 764), ethylene deriv.-oxo compd. interconversion may be achieved. F. e. s. G. Jones II, S. B. Schwartz, and M. T. Marton, Chem. Commun. 1973, 374. 

Oxetane ring from ethylene derivatives and oxo compounds... 

Carbenes, generated by photolysis of di- and tetrachloro-o-quinone diazides, react with oxetane in a 1 3 ratio to afford 15-membered crown ethers. Benzocrown ether 675 was obtained in 16% yield (91CB1865). Derivatives of macrocyclic crown ethers with four or five oxygen atoms in a ring were synthesized by Cu(acac)2-catalyzed cyclization of a,polyethylene glycols. 20-26-Membered crown-4(5) ethers 676 were prepared from the above-mentioned diazo ketones with tri- or tetra-ethylene glycols in 7-26% yields. Treatment of l,8-bis(diazoacetyl)octane with dodecane-l,12-diol under the same conditions results in a mixture of 52-membered tetraether 646 (40%) and compound 645 (81CC616). 

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