Oxygen heterocycles, saturated, reactions

Ethylene oxide 3 may be cyclodimerized to 1,4-dioxan 4 in the presence of superacids, like chlorosulfonic or perchloric acid (Equation 1). The reaction was accelerated by aprotic dipolar solvents, but was retarded by less polar solvents. Chlorosulfonic acid also catalysed ring-opening polymerization of the saturated oxygen heterocycle oxepine 5 to the polymer 6 (Equation 2). ... 

Platinum-mediated additions of alcohols to alkenes are known in their intramolecular version and have been developed by R. A. Widenhoefer and coworkers [142]. Thus, they showed that [ PtCl2(H2C-CH2)]2]/2P(4-C6H4CF3)3 is an effective catalyst for the intramolecular cyclization of 7- and 8-hydroxyolefins to saturated oxygen heterocycles under mild reaction conditions [143] (Scheme 78). 

A heterocycle is a compound with a ring that has more than one kind of atom. Nitrogen, oxygen, and sulfur are often found along with carbon in heterocyclic rings. Saturated heterocyclic amines, ethers, and sulfides usually have the same chemistry as their open-chain analogs, but unsaturated heterocycies such as pyrrole, furan, and thiophene are aromatic. All three are unusually stable, and all three undergo aromatic substitution on reaction with electrophiles. 

PREPRATION AND REACTIONS OF SATURATED PERFLUORINATED HETEROCYCLES CONTAINING OXYGEN, NITROGEN, SULFUR, SELENIUM, AND PHOSPHOROUS... 

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