Can green chemistry be the right reading key to let organocatalyst design take a step forward towards sustainable catalysis? What if the intriguing chemistry promoted by more engineered organocatalysts was carried on by using renewable and naturally occurring molecular scaffolds, or at least synthetic catalysts more respectful towards the principles of green chemistry? Within the frame of these questions, this Review will tackle the most commonly occurring organic chiral catalysts from the perspective of their synthesis rather than their employment in chemical methodologies or processes. A classification of the catalyst scaffolds based on their E factor will be provided, and the global E factor (E_G factor) will be proposed as a new green chemistry metric to consider, also, the synthetic route to the catalyst within a given organocatalytic process.

Cinchona alkaloid derivatives featuring a guanidinium group in diverse positions efficiently catalyze the cleavage of the RNA model compound 2-hydroxypropyl p-nitrophenyl phosphate (HPNP). Their high catalytic efficiency as phosphodiesterases and the potentiometric and kinetic investigations indicate the existence of a high degree of cooperation between the guanidinium group and the quinuclidine moiety with the operation of a general acid/general base mechanism. The performance of these compounds was investigated and compared in the kinetic resolution of HPNP. These data were also compared with the results of DFT calculations on the transition states of the transesterification reaction that, in part, predict and rationalize the experimental data.

A chiral heterogeneous catalyst derivative of (−)-4,5-dimethyl-3,6-bis(1-naphthyl)-1,2-benzenedisulfonimide is proven here to be efficient in a three-component asymmetric Passerini protocol, carried out in a deep eutectic solvent.