Lewis acid promoted reactions of [alpha],[beta]-unsaturated aldehydes and ketones with alkenes
Lewis acid-Promoted reactions of methyl vinyl ketone, methoxymethyl vinyl ketone and acetoxymethyl vinyl ketone with various alkenes are reported. The enones undergo [2+2] cycloaddition reactions with various substituted styrenes to give mixtures of two cyclobutane epimers. These reactions are regioselective and the yields are high. The thermodynamically less stable cyclobutane epimers are epimerized with methanolic potassium carbonate to the thermodynamically more stable cyclobutanes. Reactions of methyl vinyl ketone, methoxymethyl vinyl ketone and acetoxymetyl vinyl ketone with methylencyclohexane promoted by mixtures of TiCl[sub 4] and Ti(O[sup i]Pr)[sub 4] in various proportions give one of more of the following products; a cyclobutane, a formal ene product and a chloro-substituted product. Reactions of acetoxymethyl vinyl ketone with cyclohexene and 1-methylcyclohexene promoted by TiCl[sub 4] give mixtures of ene and chloro-substituted products and a chloro-substituted product, respectively. The chloro-substituted products are coverted to the ene products by treating with a base or by dissolution in hot methanol. Various Lewis acid-promoted intramolecular reactions of [alpha], [beta]-unsaturated aldehydes and ketones with olefins produce formal ene products and, in one cas, a bicyclo [2.2.1] heptane product. The latter product results apparently from alkylation of the Lewis acid-bound [alpha], [beta]-unsaturated carbonyl moiety at the [beta]-carbon, rearrangement of the resultant carbocation by hydride shift, followed by coupling of the enolate and carbocation moieties. A synthesis of the natural product nanaimoal is also reported.
- Research Organization:
- Kansas Univ., Lawrence, KS (United States)
- OSTI ID:
- 7107530
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
400201* -- Chemical & Physicochemical Properties
ALDEHYDES
ALKENES
CHALCOGENIDES
CHEMICAL REACTION KINETICS
CHLORIDES
CHLORINE COMPOUNDS
HALIDES
HALOGEN COMPOUNDS
HYDROCARBONS
HYDROGEN COMPOUNDS
INORGANIC ACIDS
KETONES
KINETICS
LEWIS ACIDS
ORGANIC CHLORINE COMPOUNDS
ORGANIC COMPOUNDS
ORGANIC HALOGEN COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
REACTION KINETICS
TITANIUM CHLORIDES
TITANIUM COMPOUNDS
TITANIUM OXIDES
TRANSITION ELEMENT COMPOUNDS