Environmentally benign, sequential synthesis of 3,4-dihydro-2H-1,4-benzoxazines under phase transfer catalysis conditions

Abstract

An environmentally friendly synthesis of 2-substituted 3,4-dihydro-2H-1,4-benzoxazines has been carried out in a sequential fashion through the R₄N⁺F⁻ catalyzed ring opening of epoxides with arylsulfonamides, followed by in situ cyclization of the hydroxysulfonamides thus obtained with NaOH aq. and n-C₁₄H₂₉N⁺Me₃Cl⁻.