1.3- Dipolar cycloaddition of azomethine yhdes

Bonini, B.F. Boschi, F. Franchini, M.C. Fochi, M. Fini, F. Mazzanti, A. Ricci, A. First 1,3-dipolar cycloaddition of azomethine yhdes with ( )-ethyl 3-fluoroacrylate regio- and stereoselective synthesis of enantiopure fluorinated prolines. Synlett 2006, 543-546. 

Subsequently, the one-pot organocatalytic [C+NC+CC] coupling reaction between aldehydes 204, dialkyl-2-aminomalonate 205 and a,p-unsaturated aldehydes 28 was achieved with highly chemo-and enantioselectivity by Cordova, et al Scheme 3.66 [83]. The mechanism involved the 1,3-dipolar cycloaddition of azomethine yhde and chiral iminium intermediate, via re-facial and endo-addition to give the pyrroUdine derivatives. Later, the authors reported a similar approach to 5-hydroxypyrrolidme 208 from acylaminomalonates 207 and a,P-unsaturated aldehydes 28, Scheme 3.67 [84]. 

The same scheme is used to follow the Diels-Alder reaction of 3-styrylchro-mones [81] and intramolecular 1, 3-dipolar cycloaddition of azomethine yhdes [82]. The yield of the product was about 80% in 15 min of microwave irradiation. These reactions were foimd to take much longer time through conventional heating method. 

Cabrera, S., Arrayds, R. G., Carretero, J. C. (2005). Highly enantioselective copper(I)-fesulphos-catalyzed 1,3-dipolar cycloaddition of azomethine yhdes. Journal of the American Chemical Society, 127, 16394-16395. 

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