Diastereoselective synthesis of α, α, α′-trisubstituted pyrrolidines and piperidines by directed sequential lithiation/alkylation. Issue 1 (1st January 2015) - Beng, Timothy K.
Graphical abstract: Abstract: The stereocontrolled synthesis of α, α, α′-trisubstituted pyrrolidines and piperidines has been accomplished through α′-lithiation/trapping of the corresponding α, α-disubstituted Boc-protected azaheterocycle with various electrophiles. The relative configuration of the major diastereomer has the α′-substituent trans to the α-aryl group in the pyrrolidines but cis to the α-aryl group in the piperidines. The diastereoselectivity of the lithiation/alkylation of pyrrolidines is unaffected by TMEDA but decreases in the presence of (−)-sparteine in diethyl ether.