- Unusual cyclodimerization of small cyclic ethers via neighboring carbonyl-group participation and cation transfer
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Oxetanes having both a carbonyl functional group and a phenyl group at the 3-position bring about unusual cyclodimerization under the influence of trifluoromethanesulfonic acid, to give a cis/trans-isomer mixture of substituted 1,3-dioxanes via neighboring carbonyl-group participation, cation transfer including phenonium rearrangement, and cyclodimerization. Oxiranes having a carbonyl functional group also undergo a similar cyclodimerization to form a 1,3-dioxolane ring. No phenyl substituent is required in the cases of the oxiranes, because the cation transfer process involves a 1,2-hydride shift alone. These five- and six-membered cyclic acetals are quite different from ring-expanded cyclic ether dimers expected simply from the back-biting reaction known in the cationic ring-opening polymerization of oxiranes and oxetanes.
- Kanoh, Shigeyoshi,Nishimura, Tomonari,Naka, Masashi,Motoi, Masatoshi
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p. 7065 - 7074
(2007/10/03)
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