X=Y-ZH COMPOUNDS AS POTENTIAL 1,3-DIPOLES. PART 29. THE IMINIUM ION ROUTE TO AZOMETHINE YLIDES. REACTION OF CYCLIC SECONDARY AMINES WITH MONO- AND BI- FUNCTIONAL ALDEHYDES

Article abstract of DOI:10.1016/S0040-4020(01)96014-4

1,2,3,4-Tetrahydro-isoquinoline and -β-carboline react with a range of mono- and bi- functional aldehydes to give azomethine ylides.The anti-dipole is formed stereospecifically or, in the case of benzaldehyde and 2-methylbenzaldehyde, stereoselectively.The effect of the structure of the aldehyde on the stereochemistry of the derived azomethine ylide is rationalised in terms of steric and electronic effects.Inter- and intra-molecular trapping of the azomethine ylides gives cycloadducts in good yield.