RESUMO
The reaction between 3-methyl-4-nitro-5-styrylisoxazoles and ethyl isocyanoacetate proceeded under phase transfer catalysis to give enantioenriched monoadducts in high enantiomeric excess (up to 99% ee). The resulting adducts were subsequently cyclised to give 2,3-dihydropyrroles and substituted pyrrolidines in identical high ees and as a single diastereoisomer.
Assuntos
Acetatos/química , Isoxazóis/química , Nitrocompostos/química , Pirróis/síntese química , Pirrolidinas/síntese química , Acetatos/síntese química , Catálise , Ciclização , Isoxazóis/síntese química , Metilação , Nitrilas/síntese química , Nitrilas/química , Nitrocompostos/síntese química , Pirróis/química , Pirrolidinas/química , EstereoisomerismoRESUMO
Heavily substituted cyclopropane esters were prepared in high yields, complete diastereoselection and high (up to 96%) enantioselectivity. The reaction described herein entailed reacting 4-nitro-5-styrylisoxazoles, a class of cinnamate synthetic equivalent, with 2-bromomalonate esters under the catalysis of 5 mol% of a Cincona derived phase-transfer catalyst. The reaction allowed multi-gram preparation of desired products.
