title: An efficient synthesis of five-membered cyclic ethers from 1,3-diols using molecular iodine as a catalyst.
abstract: Intramolecular cyclic etherification of 1,3-diols was investigated using iodine as a catalyst under solution reaction conditions. Compounds containing five-membered ether rings were obtained. Propella ether (11-oxatricyclo[4.4.3.0(1,6)]tridecane) was conveniently synthesized from 1,3-diol (6-(2-hydroxyethyl)spiro[4.5]decan-6-ol) in 97% yield via carbon skeleton rearrangement. Spiroethers and bicyclic ethers were also obtained from the corresponding 1,3-diols in yields of over 77%. The most suitable reaction conditions were a temperature of 80 degrees C, a 1:0.2 molar ratio of 1,3-diol:iodine, and a time period of 8 h. In addition, terpenoic ethers were efficiently synthesized from the corresponding 1,3-diols, derived from (+)-camphor and (-)-fenchone, via skeleton rearrangement. In particular, the reaction of the 1,3-diol derived from (+)-camphor proceeded smoothly at room temperature with a yield of 91%. The yield of the cyclic ether using iodine as a catalyst was comparable to the method using sulfuric acid.
authors.affiliation: Education center, Faculty of engineering, Chiba Institute of Technology, Narashino-shi, Chiba, Japan. yoshio.kasashima@it-chiba.ac.jp <yoshio.kasashima@it-chiba.ac.jp>
authors.forename: Yoshio
authors.initials: Y
authors.lastname: Kasashima
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Fujimoto
authors.forename: Takashi
authors.initials: T
authors.lastname: Mino
authors.forename: Masami
authors.initials: M
authors.lastname: Sakamoto
authors.forename: Tsutomu
authors.initials: T
authors.lastname: Fujita
mesh_terms: D000438:Alcohols / Q000737:chemistry*; D002164:Camphor / Q000737:chemistry*; D002384:Catalysis; D003500:Cyclization; D004988:Ethers, Cyclic / Q000138:chemical synthesis*; D007455:Iodine / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D008956:Models, Chemical; D012997:Solvents / Q000737:chemistry; D013237:Stereoisomerism; D013696:Temperature; D013997:Time Factors
chemical_list: D000438:Alcohols; D004988:Ethers, Cyclic; D012997:Solvents; D002164:Camphor; D007455:Iodine