Abstract
The dearomatising anionic cyclisation of tertiary naphthamides bearing chiral N-substituents (such as α-methylbenzyl) is stereospecific and retentive not because of a configurationally stable organolithium intermediate but because the starting material exists as two atropisomers at -78°C, of which only one is lithiated. The initially formed ortholithiated amide can be trapped with MeI to give single diastereoisomers of atropisomeric amides bearing chiral N-substituents. Given time, even in the absence of DMPU, the ortholithiated amide undergoes anion translocation to an α-lithiated species, which can cyclise only to one diastereoisomer of the product, leading to the observed stereospecificity.
Original language | English |
---|---|
Pages (from-to) | 8327-8331 |
Number of pages | 5 |
Journal | Tetrahedron Letters |
Volume | 40 |
Issue number | 48 |
DOIs | |
Publication status | Published - 26 Nov 1999 |