Oxetanes ring opening

The reaction of 3-phenyloxetane (10) with nitric acid in dichloromethane and trichloromethane under anhydrous conditions has been investigated.35 Quantitative conversion into 2-(nitrophenyl)propane-l,3-diol dinitrates occurs. The substrate reacts through its majority hydrogen-bonded complexed form initially by a mixture of aromatic nitration and oxetane ring opening. The nitration, perhaps surprisingly, proceeds at a rate comparable to that of / -dichlorobenzene. 

As an extension of this work, photoinduced [2+2]-cycloadditions of 1-acetylisatin (13) with cyclic enolethers (furan, benzofuran, 2-phenylfuran, 8-methoxypsoralen), and acyclic enolethers (//-butyl vinyl ether and vinyl acetate) were investigated which afforded the spiro-oxetanes in high yields (82-96%) and with high regio- and diastereoselectivity (Sch. 4) [19]. Treatment of the furan-derived oxetane 15 with acid resulted in oxetane ring opening and yielded the 3-(furan-3-yl)indole derivative 16. 

It was assumed that the oxetane ring opening occurred with inversion of configuration, leading to the assignment of (99) as the tosylate structure. 

Oxetans.—Ring Opening. Electrophilic attack on the oxetan ring, followed by ring opening, has been accomplished with a variety of reagents. In the presence... 

Besides to the classes of taxanes discussed before, there are also some miscellaneous taxanes having a diversity of stmctural modifications in the tricyclic skeleton. Some examples include taxine A with a unique rearranged skeleton brevifoliol (natural diterpene isolated from Taxus baccata) and taxchinine A (acetoxybrevifohol) contain a five-membered A ring in place of the usual six-membered ring hydroxylated analogs of the taxanes which have an exocyclic double bond between C-4 and C-20 (class A) and can also be viewed as the oxetane ring-opened compounds of the taxane class D [19]. 

Without additional reagents lyl-Alkoxyhalides from oxo eompounds s. U, 908 Halogenhydrins from oxido compounds s. A, 475 s. a. J. L. Bose, A. B. Foster, and R. W. Stephens, Soc. 1959, 3314 Reactions with carbamyl chloride Chlorourethans s. 11, 590 Chloroallophanates from allophanyl chloride s. 11, 591 Oxetane ring opening lodohydrins from cyclic ethers s. 12, 626 Tetrahydrofuran ring opening s. 11, 1 w.a.r. CO C(OR)Hal C C -> C(OH)CHal... 

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