198546-63-3Relevant articles and documents
A mechanistic and structural investigation of the (-)-sparteine mediated asymmetric benzylic lithiation substitution reactions of N-Boc-N-(p-methoxyphenyl)benzylamine
Faibish, Neil C.,Park, Yong Sun,Lee, Steven,Beak, Peter
, p. 11561 - 11570 (2007/10/03)
Mechanistic and structural studies show the high enantioenrichments in the products from lithiation substitutions of N-Boc-N-(p-methoxyphenyl)benzylamine (1) by n-BuLi/(-)-sparteine (6) arise from an enantioselective deprotonation of 1 to provide configurationally stable (R)-2/6. NMR spectroscopy establishes that 13C, 6Li labeled (R)-2/6 and (S)-2/6 are monomeric with lithium complexed to the benzylic position, the carbonyl of the Boc group and (-)-sparteine. Deprotonations of the tertiary protons in (R)- and (S)-N-Boc-N-(p-methoxyphenyl)-α-methylbenzylamine ((R)-8 and (S)-8) with n-BuLi/TMEDA provide (R)-9/TMEDA and (S)-9/TMEDA, respectively, with high enantioenrichments. Absolute configurations assigned to (R)-2 and (R)-1-d1 allow analysis of the electrophile dependent stereochemistry of the reactions of these configurationally stable organolithium intermediates.