One-pot operations are an effective method for both carrying out several transformations and forming several bonds in a single-pot, while at the same time cutting out several purifications, minimizing chemical waste generation, and saving time. Thus, a one-pot reaction can be not only efficient, but also green and environmentally friendly, and “pot-economy” should be considered in planning a synthesis.[1]
On the other hand, organocatalyst is an effective catalyst to carry out several reactions in a same vessel. Our group[2] and Jørgensen’s group[3] independently discovered that diphenylprolinol silyl ether, which is easily synthesized from proline, is an effective organocatalyst in the reaction involving enamine and iminium ion as reactive intermediates. We have been investigating the application of this organocatalyst to the one-pot synthesis of biologically active molecules.
We have already reported three pot synthesis of (-)-oseltamivir, a neuraminidase inhibitor used in the treatment of human influenza, based on the diphenylprolinol silyl ether mediated Michael reaction of aldehyde and nitroalkene as a key step. We have accomplished 60 minutes total synthesis of (-)-oseltamivir for “time-economy“,[4] and the multistep one continuous-flow synthesis of the same molecule.[5] We also synthesized estradiol methyl ether via five pot.[6] Moreover we have recently accomplished one-pot 152 minutes synthesis of Corey lactone.[7] A recent progress in one-pot synthesis will be presented.

References:
1. Y. Hayashi, Chem. Sci. 2016, 7, 866.
2. Y. Hayashi, H. Gotoh, T. Hayashi, M. Shoji, Angew. Chem. Int. Ed. 2005, 44, 4212.
3. M. Marigo, T. C. Wabnitz, D. Fielenbach, K. A. Jørgensen, Angew. Chem. Int. Ed. 2005, 44, 794.
4. Y. Hayashi, S. Ogasawara, Org. Lett. 2016, 18, 3426.
5. S. Ogasawara, Y. Hayashi, Synthesis 2017, 49, 424.
6. Y. Hayashi, S. Koshino, K. Ojima, E. Kwon, Angew. Chem. Int. Ed. 2017, 56, 11812.
7. N. Umekubo, Y. Suga, Y. Hayashi, Chem. Sci. 2020, ASAP DOI: org/10.1039/C9SC05824A