Pipecolinic add

Employing a flow rate of 1 pi min 1 and a residence time of 0.86 min, the authors obtained 87% conversion of 161, exhibiting 22% selectivity for pipecolinic acid (160 and 162) and 14% L-pipecolinic add (160). For comparative purposes, the authors also performed the reaction in batch, employing 2 wt% Pt-loaded Ti02 particles, which afforded the same surface-to-volume ratio of catalyst as the TCM, where a 70 times longer reaction time (60 min) was required in order to obtain analogous results to the TCM. The authors conduded that the increased readion effidency, within the TCM, was attributable to the efficient irradiation of the readion mixture however, for a true comparison they noted that measurement of the quantum yield of each system would be required. 

Zhao et al. accomplished the arylation of >P(0)H species in the presence of copper(i) iodide and a base in toluene or DMF. The use of proline or pipecolinic add as ligands greatly improved the efficiency of the coupling reactions (Scheme 24). ... 

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