Tandem Overman rearrangement and intramolecular amidomercuration reactions.: Stereocontrolled synthesis of cis- and trans-2,6-dialkylpiperidines

Hg(II)-mediated tandem Overman rearrangement and intramolecular amidomercuration reactions were proven to provide a convenient tool for the stereoselective synthesis of cis- and trans-2,6-disubstituted piperidines. Thus, upon treatment with Hg(OTFA)(2) in THF, the trichloroacetimidate I directly transformed into the 2,6-dialkyl piperidine 2 with almost exclusive trans selectivity. The amiodomercuration reaction of the carbamate 7 by Hg(OTFA)2 in nitromethane showed an excellent cis selectivity. Also reported is the stereoselective synthesis of solenopsin A and isosolenopsin A.