Studies on Instructive Construction of <i>exo</i>-Olefin Terminated Five- and Six-Membered Nitrogen Heterocycles: SmI<sub>2</sub>-Mediated Intramolecular Cyclization of Haloalkynals
pyrrolidine and piperidine frameworks was developed by employing SmI2-mediated intramolecular radical cyclization of haloalkynaks. The radical cyclization affording 2,3-disubstituted pyrrolidines and piperidines proceeded in a highly stereoselective manner. However, decreasing stereoselectivety was observed in the preparation of 2,4-disubstituted pyrrolidine and 3,4-disubstituted piperidinederivatives in the
1,2-Cyclic Sulfamidates as Versatile Precursors to Thiomorpholines and Piperazines
作者:Andrew J. Williams、Suda Chakthong、Diane Gray、Ron M. Lawrence、Timothy Gallagher
DOI:10.1021/ol027418h
日期:2003.3.1
Graphics1,2-Cyclic sulfamidates undergo regiospecific nucleophilic displacement with either methyl thioglycolate or a-amino esters, followed by lactamization (thermal, base-mediated, or cyanide-catalyzed), to give thiomorpholin-3-ones and piperazin-2-ones.