92757-93-2Relevant articles and documents
Substitution and Elimination Reactions of 3- and 4-Alkyl-2H-1-benzopyrans with Organoaluminium and Organomagnesium Reagents
Alberola, Angel,Ortega, Alfonso Gonzalez,Pedrosa, Rafael,Bragado, Jose Luis Perez,Vicente, Martina
, p. 1259 - 1262 (2007/10/02)
2,3-Dialkyl- and 2,2,3-trialkyl-2H-1-benzopyrans react with triethylaluminium or ethylmagnesium bromide yielding substituted o-allylphenols in good yield.The reactions of 2,3-dialkyl-2H-1-benzopyrans are stereoselective.Either the E or Z isomers can be formed preferentially depending upon the experimental conditions; the stereoselectivity increases with the bulk of the alkyl substituent at C-3.However 2,4-dialkyl- and 2,2,4-trialkyl-2H-1-benzopyrans lead to o-allylphenols only with ethylmagnesium bromide; the mixture of E and Z isomers thus formed was found to be very difficult to separate.
