An effective and highly regio- and diastereoselective one-pot method for the synthesis of new polynuclear dispiroheterocyclic systems with five stereogenic centers (dispiro[imidazo[4,5-e]thiazolo[3,2-b]-1,2,4-triazine-6,3'-pyrrolidine-2',3''-indoles]) comprising pyrrolidinyloxindole and imidazo[4,5-e]thiazolo[3,2-b]-1,2,4-triazine moieties has been developed. The method relies on a 1,3-dipolar ...

A facile and efficient one-pot synthesis of pyrrolidines and dispiro pyrrolidines/pyrrolizidines has been accomplished by the 1,3-dipolar cycloaddtion reaction of azomethine ylides generated insitu from paraformaldehyde/ninhydrin and secondary amino acids with electron-deficient dipolarophiles in good yield. The reaction proceeded with high regio and stereoselectivity. The products have been ch...

1,3-Dipolar cycloaddition of azomethine ylides derived from acenaphthylene-1,2-dione and 5methyl-benzo[b]-thiophene-2,3-dione with L-proline, thiazolidine-4-carboxylic acid and 1,2,3,4tetrahydroisoquinoline-3-carboxylic acid with various electron deficient dipolarophiles leads to the formation of novel spiroheterocycles having two or more chiral centers. Semiempirical studies have been performe...

This paper describes the synthesis of precursors with a benzo[b]furan skeleton for the intramolecular 1,3-dipolar cycloaddition of azomethine ylides prepared from N-substituted 3-allyl-aminobenzo[b]furan-2-aldehydes and secondary amines derived from α-amino acid esters. Reactions were initiated by heating. The products consisted of four fused rings with three stereogenic centers. Their structur...

Abstract One-pot two sequential [3 + 2] cycloadditions of azomethine ylides with different dipolarophiles for diastereoselective synthesis spirooxindole pyrrolizidines are introduced. This one-pot involving five components generates a highly condensed ring system bearing seven stereocenters diastereoselectively. The new method has high pot, atom, and step economy. Only equivalents water release...

Chiral complexes formed by phosphoramidites such as (Sa,R,R)-9 and Cu(OTf)2 are excellent catalysts for the general 1,3-dipolar cycloaddition between azomethine ylides and nitroalkenes affording the corresponding tetrasubstituted proline esters mainly as exo-cycloadducts in high er at room temperature. The exo-cycloadducts can be obtained in enantiomerically pure form just after simple recrysta...

the development of multicomponent reactions (mcrs) designed to produce elaborate biologically active compounds has become an important area of research in organic, combinatorial, and medicinal chemistry. a comparative study of the synthesis of new bis-spiro-oxindolo(pyrrolizidines/pyrrolidines) ring systems by the cycloaddition of azomethine ylides generated by a decarboxylative route from sarc...

A number of novel spiro-pyrrolidines/pyrrolizines derivatives were synthesized through [3+2]-cycloaddition of azomethine ylides with 3,5-bis[(E)-arylmethylidene]tetrahydro-4(1H)-pyridinones 2a-n. Azomethine ylides were generated in situ from the reaction of 1H-indole-2,3-dione (isatin, 3) with N-methylglycine (sarcosine), phenylglycine, or proline. All compounds (50 μM) were evaluated for their...