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Synthetic Applications and Inversion Dynamics of Configurationally Stable 2‑Lithio-2-arylpyrrolidines and -piperidines

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journal contribution
posted on 12.09.2012 by Timothy K. Beng, Jin Sun Woo, Robert E. Gawley
In diethyl ether, N-Boc-2-lithio-2-arylpiperidines have been found to be configurationally stable at −80 °C, whereas N-Boc-2-lithio-2-arylpyrrolidines are configurationally stable at −60 °C. Several tertiary benzylic carbanions derived from enantioenriched 2-aryl heterocycles have been successfully alkylated or acylated with little to no loss of enantiopurity. The scope of the reactions has been explored. The enantiomerization dynamics of N-Boc-2-lithio-2-phenylpyrrolidine and N-Boc-2-lithio-2-phenylpiperidine have been studied in the presence of different solvents and achiral ligands.