Synthesis of oxetanes
The intramolecular O-vinylation of γ-bromohomoallylic alcohols with 10 mol % of CuI as the catalyst and 20 mol % of 1,10-phenanthroline as the ligand in refluxing MeCN led to the convenient formation of the corresponding 2-methyleneoxetanes in good to excellent yields via a 4-exo ring closure. 4-exo cyclization is preferred over other modes of cyclization.
Y. Fang, C. Li, J. Am. Chem. Soc., 2007, 129, 8092-8093.
An efficient solvent-controlled oxidative cyclization of Michael adducts of malonates with chalcones with the combination of iodosobenzene and tetrabutylammonium iodide enables the divergent synthesis of highly functionalized oxetanes and cyclopropanes in good yields with high diastereoselectivity.
Y. Ye, C. Zheng, R. Fan, Org. Lett., 2009, 11, 3156-3159.
3-(Silyloxy)oxetanes are obtained by irradiating mixtures of aromatic aldehydes and silyl enol ethers in benzene as the solvent. Under similar conditions, but in acetonitrile rather than benzene, the Paternò-Büchi reaction of N-acyl enamines gives the corresponding protected 3-aminooxetanes. The reactions occur with high diastereoselectivity.
F. Vogt, K. Jödicke, J. Schröder, T. Bach, Synthesis, 2009, 4268-4273.