120783-56-4Relevant articles and documents
Conversion of Unsaturated Alcohols into Functionalized Tetrahydrofurans and Tetrahydropyrans via Nitrile Oxide Dipolar Cycloadditions
Hassner, Alfred,Murthy, K. S. K.,Padwa, Albert,Chiacchio, Ugo,Dean, Dennis C.,Schoffstall, Allen M.
, p. 5277 - 5286 (2007/10/02)
The intramolecular nitrile oxide cycloaddition (INOC) of a series of unsaturated oximino ethers has been investigated.The synthesis of the olefinic nitrile oxides involves treating an unsaturated alcohol with a α-bromoalkanal O-(trimethylsilyl)oxime in the presence of fluoride ion followed by subsequent sodium hypochlorite oxidation.The nitrile oxides were not isolated but spontaneously underwent intramolecular cycloaddition to give fused five- and six-membered ring ethers.The preferred stereoisomer in the formation of the five-membered ring ethers is trans, whereasin the six-membered ring ethers the cis isomer predominates.MM2 calculations help rationalize the observed stereoselectivity.The ratio of diastereomeric products from the INOC reaction appears to correlate with product stabilities.Simple heating of some of the oximino ethers led to intramolecular cycloaddition.The ring closure apparently proceeds subsequent to a tautomeric equilibration of the oxime with a transient nitrone which is trapped by the neighboring ?-bond.
FORMATION OF FUNCTIONALIZED CYCLIC ETHERS BY INTRAMOLECULAR NITRILE OXIDE CYCLOADDITIONS
Padwa, Albert,Chiacchio, Ugo,Dean, Dennis C.,Schoffstall, Allen M.,Hassner, Alfred,Murthy, K. S. K.
, p. 4169 - 4172 (2007/10/02)
The reaction of O-trimethylsilyl α-bromo aldoximes with unsaturated alcohols produces oximino ethers which can be readily oxidized with sodium hypochlorite.The transient nitrile oxide intermediate formed undergoes spontaneous cyclization affording fused i
