ABSTRACT
P(n)Bu(3)-catalyzed cyclization reactions of salicylaldimines and salicylaldehydes with ethyl 2,3-butadienoate gave the corresponding functionalized chromans in moderate to good yields in THF under mild conditions. The new reaction provides a new method for the synthesis of biologically active chroman products.
Subject(s)
Aldehydes/chemistry , Alkadienes/chemistry , Chromans/chemistry , Esters/chemistry , Imines/chemistry , Phosphines/chemistry , Catalysis , Crystallography, X-Ray , Models, Molecular , Molecular StructureABSTRACT
A P(p-FC(6)H(4))(3)-catalyzed tandem reaction between ethyl 2,3-butadienoate and nitroalkenes has been developed, which involves a [3 + 2] cycloaddition and a subsequent umpolung addition. The asymmetric version of this tandem reaction has also been investigated by using chiral phosphanes.
ABSTRACT
Lewis base catalyzed reactions of N-Boc-imines and ethyl 2,3-butadienoate were investigated systematically. The normal aza-Morita-Bylis-Hillman products were obtained in good to excellent yields catalyzed by DABCO. When PPh(3) was used as the catalyst, novel rearrangement product (E)-ethyl 2-((Z)-(tert-butoxycarbonylimino)(aryl)methyl)but-2-enoates could be formed in moderate yields.
ABSTRACT
Ethyl 5,5-diarylpenta-2,3,4-trienoates were synthesized and utilized in the phosphine-mediated [3+2] cycloaddition reactions with arylmethylidenemalononitriles and N-tosylimines in the presence of tributylphosphine. These reactions provide an easy access to a variety of novel polysubstituted cyclopentenes or pyrrolidines in good to excellent yields under mild conditions.
Subject(s)
Cyclopentanes/chemical synthesis , Imines/chemistry , Nitriles/chemistry , Phosphines/chemistry , Pyrrolidines/chemical synthesis , Cyclization , Cyclopentanes/chemistry , Molecular Structure , Pyrrolidines/chemistry , Stereoisomerism , Tosyl Compounds/chemistryABSTRACT
A three-component reaction of beta-nitrostyrene, arylmethylidenemalononitrile and malononitrile catalyzed by imidazole produced the corresponding polysubstituted cyclohexene derivatives in moderate to good yields under mild conditions. A further improvement of this three-component reaction has also been achieved by starting from a commercially available aromatic aldehyde, nitromethane and malononitrile to give the products in moderate yields.
