Prolines, polysubstituted

Another example to illustrate the synthesis of proline derivatives 78 was published by Vicario and coworkers in 2013 [48]. Starting from aromatic aldehydes, diethyl malonate, and a,p-unsaturated aldehydes upon catalysis of unprotected diphenylprolinol, the synthesis of polysubstituted pyrrolidines was achieved in a one-pot condensation and [3+2] cycloaddition reaction in aqueous medium. 

The 3 + 2-cycloaddition reaction of azomethine ylides with c-deficient alkenes produced polysubstituted l- and D-unnatural prolines. Also, phosphoramidite-(7u(OTf)2 complexes catalyse the 1,3-dipolar cycloaddition reactions of azomethine ylides with nitroalkenes to yield exo-tetrasubstituted proline esters." The 1,3-dipolar cycloaddition of non-stabilized azomethine ylides, from iV-alkyl-a-amino acids and aldehydes, with 3-substituted coumarins provides l-benzopyrano[3,4-c]pyrrolidines in good yields and high regio- and stereo-selectivity." The organocatalytic 1,3-dipolar cycloaddition of azomethine ylides, derived from azlactones, with methyleneindolinones produced spirooxindoles with high yields (up to 95%) and high diastereo- (93 7 dr) and enantioselectivity (98% ee). ... 

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