Synthesis of 6- and 7-Membered <i>N</i>-Heterocycles Using α-Phenylvinylsulfonium Salts
作者:Johnathan V. Matlock、Thomas D. Svejstrup、Pradip Songara、Sarah Overington、Eoghan M. McGarrigle、Varinder K. Aggarwal
DOI:10.1021/acs.orglett.5b02516
日期:2015.10.16
A concise synthesis of stereodefined C-substituted morpholines, piperazines, azepines, and oxazepines in moderate to excellent yields (27% to 75%) is reported by reaction of 1,2- or 1,3-amino alcohol/1,2- or 1,3-diamine with an alpha-phenylvinylsulfonium salt. High levels of regio- and diastereoselectivity (from 2:1 to >20:1) are observed through judicious choice of base (Cs2CO3) and solvent (CH2Cl2). Reactions are performed at ambient temperature and open to air and do not require anhydrous solvent. The deprotection of the N-sulfonamide protecting groups (N-Ts and N-Ns) is also demonstrated. Factors affecting regio- and diastereocontrol are discussed.