Tk. Yang et al., STEREOSELECTIVE SYNTHESIS OF 2,6-DISUBSTITUTED PIPERIDINE ALKALOIDS VIA TICL4 INDUCED IMINIUM ION CYCLIZATION OF ALPHA-CYANOAMINES, Tetrahedron letters, 35(21), 1994, pp. 3581-3582
The stereoselective cyclization of an alpha-cyanoamine containing a vi
nyl group induced by TiCl4 in a methylene chloride solution, produces
cis 2,6-dialkylpiperidine; whereas a similar reaction of an alpha-cyan
oamine containing a silyl substituted vinyl group gave the correspondi
ng trans isomer only.