Oxetane

Abstract: An intramolecular Heck reaction (90 → 91) serves as the key step in the total synthesis of the titled compounds. The synthetic route is based on utilizing the Wieland−Miescher ketone (5) as a matrix to provide the C and D rings of the targets and to provide functionality implements for joining this sector to an A ring precursor (6). Catalytically induced enantiotopic control and early emplacement of the oxetane are other features of the route.

Abstract: Ylides are nucleophiles that bear a unique leaving group, LnM, and can attack aldehydes, ketones, imines, and electron-deficient alkenes. Over the course of the reaction, they react with C═X (X = C, N, O, etc.) double bonds to form betaine or oxetane intermediates, which further eliminate the heteroatom-containing group in one of two ways to give the corresponding olefination or cyclization product. Since the discovery of the Wittig reaction, ylide olefination has developed as one of the most useful approaches in constructing carbon−carbon double bonds. These reactions provide unambiguous positioning of the C−C double bond and good stereoselectivity. Researchers have also widely used ylides for the synthesis of small ring compounds such as epoxides, cyclopropanes, and aziridines. However, the use of ylides to prepare larger cyclic structures was very limited. This Account outlines our recent work on ylide-initiated Michael addition/cyclization reactions. By altering the heteroatoms and the ligands of the ...

Abstract: HYDROXY TERMINATED POLYETHERS ARE OBTAINED BY REACTING (1) EPOXIDE AND OXETANE MONOMERS WITH (2) A TELOGEN AT LEAST PARTIALLY SOLUBLE WITH THE MONOMERS, REACTIVE WITH SAID MONOMERS AND BEING SELECTED FROM THE GROUP CONSISTING OF ORGANIC HYDROXY CONTAINING COMPOUNDS, SULFHYDRYL CONTAINING COMPOUNDS, ALDEHYDES AND KETONES, SUCH AS METHANOL, HEXANEDIONE-2,5, ACETONE, ETHYLENE GLYCOL, TRIMETHYLOL PROPANE, ETC., USING (3) IN ADMIXTURE THEREWITH A CATALYSTS CERTAIN DOUBLE METAL CYANIDE COMPLEXES WHICH PREFERABLY HAD BEEN TREATED WITH ORGANIC MATERIALS LIKE ALCOHOLS, ETHERS, ESTERS AND SO FORTH. A FEATURE OF THE PROCESS OF THE PRESENT INVENTION IS THE PREPARATION OF HIGH MOLECULAR WEIGHT DIOLS, TRIOLS, ETC. WITHOUT APPRECIABLE END GROUP UNSATURATION, AND THE USE OF CERTAIN SOLVENTS WITH PARTICULAR MONOMERS AND CATALYSTS TO ALSO ACHIEVE THESE RESULTS. THE PRODUCTS OF THE PRESENT PROCESS ARE USEFUL AS NONIONIC SURFACE ACTIVE AGENTS, AS LUBRICANTS AND COOLANTS, AS TEXTILE SIZES, AS FILM FOR PACKAGING AND IN THE PREPARATION OF SOLID OR FLEXIBLE POLYURETHANES BY REACTION WITH POLYISOCYANATES.

Abstract: The four-membered oxetane ring has been increasingly exploited for its contrasting behaviors: its influence on physicochemical properties as a stable motif in medicinal chemistry and its propensity to undergo ring-opening reactions as a synthetic intermediate. These applications have driven numerous studies into the synthesis of new oxetane derivatives. This review takes an overview of the literature for the synthesis of oxetane derivatives, concentrating on advances in the last five years up to the end of 2015. These methods are clustered by strategies for preparation of the ring and further derivatization of preformed oxetane-containing building blocks. Examples of the use of oxetanes in medicinal chemistry are reported, including a collation of oxetane derivatives appearing in recent patents for medicinal chemistry applications. Finally, examples of oxetane derivatives in ring-opening and ring-expansion reactions are described.