Convenient synthesis of isoxazolines via tandem isomerization of allyl compounds to vinylic derivatives and 1,3-dipolar cycloaddition of nitrile oxides to the vinylic compounds

A novel effective method for the synthesis of new isoxazolines via tandem isomerization of QCH(X)CHCH(Y) to QC(X)CHCH2(Y) (Q = RO, RS, R2N, R3Si, etc.; X = H, R, OR; Y = H, R; R = alkyl, aryl) catalyzed by ruthenium complexes and 1,3-dipolar cycloaddition of the latter compounds to arenenitrile oxides is presented. The cycloaddition of QCH(X)CHCH(Y) to 2,6-dichlorobenzonitrile oxide is also described. The regio- and stereoselectivity of the cycloaddition of nitrile oxide to allyl and 1-propenyl (vinylic in general) compounds is discussed.

Q = RO, RS, R2N and others (R = alkyl and aryl); X, Y = H, R, RO; Ar = 2,6-dichlorophenyl, 2,4,6-trimethylphenyl, 2,4,6-trimethoxyphenyl, 4-chlorophenyl.