Prolinol carbon ethers-catalysed reactions

In contrast to the plethora of methodologies showing stereoselective applications of the Jorgensen-Hayashi catalyst (Chapter 8), a few reports have addressed the catal3dic ability of prolinol carbon-ethers in asymmetric synthesis. These procedures focused on the employment of commercially available (5)- or (R)-2-metho3qmiethylpyrrolidine, a scaffold originally 

Polystyrene supported versions of catalyst Id have been reported/ In addition, Frechet and coworkers demonstrated that catalyst Id can be encapsulated in the core of a soluble star polymer, which enables reagents to diffuse, allowing catalysis to take place/ Interestingly, the concurrent mixing of different chiral and achiral catalysts encapsulated in a similar manner onto different star polymers enabled one-pot multicomponent asymmetric cascade reactions of otherwise incompatible catalysts. 

The methodologies herein illustrated have a major appealing feature based on the use of commercially or readily available organocatalysts derived from L-proline, which is a cheap source. Important chiral nonracemic targets are obtained working under mild reaction conditions. With a view to large-scale applications, attempts aimed at employing water and alcohols as solvents or cosolvents have been addressed. 

Asymmetric Organocatalysis, Science of Synthesis, ed. B. List and K. Maruoka, Thieme, Stuttgart, 1st edn, 2012. 

Lattanzi, C. De Fusco, A. Russo, A. Poater and L. Cavallo, Chem. Commun., 2012, 48, 1650. 

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