Asymmetric Organocatalytic Reactions under Ball Milling - Ball Milling Towards Green Synthesis: Applications, Projects, Challenges - page 91

in asymmetric synthesis is relatively recent, but the accumulated obser-
vations already provide evidence that this methodology generally affords
higher stereoselectivity, higher yields, and cleaner reaction products. Fur-
thermore, the technique can be scaled-up, 49 and it is already being applied
in materials science and large-scale enterprises such as the paint and
pharmaceutical industries.
Nevertheless, the field is still open to experimental modifications, both by
the experimental practitioner and by instrument developers, in order to
achieve better control of the reaction conditions, as well as to reach a better
understanding of the reaction mechanism in the absence of solvent and
under purely mechanical activation. Particularly relevant are the very recent
advances in real-time and in situ monitoring of mechanochemical milling
reactions. 50 Of course, the rapid development of asymmetric organocatalysis
in solution offers limitless possibilities for application and study under
solvent-free, ball-milling conditions. Finally, additional innovations in

the field are possible by means of the combination of metallic and

organocatalysts. 51

Acknowledgements
We are indebted to Jos´ Gregorio Hern´ndez for a careful revision of the
manuscript prior to submission.

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