Sulfinylimines–Induced Asymmetric Synthesis Of Chiral Beta–Chlorinated Amines And 1,3–Diamines

This paper studied the asymmetric synthesis of the beta–chlorinated amines and1,3–diamines.1. Protocols for the asymmetric synthesis of β,β–dichlorinated amines, β–chlorinated amines, and α–chlorinated aziridines are presented. Diastereoselective synthesis ofβ,β–dichlorinated amines was achieved based on nucleophilic dichloromethylation of aromatic N-tert-butylsulfinyl aldimines with(dichloromethyl)trimethylsilane at –70 oC.Slowly warming the reaction mixture up to romm temperature gave α–chloro cis–aziridines.Additionally, with Bu3 SnH as the reductant, β,β–dichlorinated amines were readily obtained from easily accessible α–(trichloromethyl)amines via mono–dechlorination.Subsequent radical mono–dechlorination of the β,β–dichlorinated amines give the corresponding β–chlorinated amines in good to excellent yields. In addition, α–chlorinated cis-aziridines can also be prepared from β,β–dichlorinated amines based on an intramolecular substitution reaction.2. A highly diastereoselective and concise synthesis of 2-sulfonylated 1,3-diamines was developed, based on a double–addition reaction of methyl phenyl sulfone and methyl2-pyridylsulfone with N-tert-butylsulfinyl imines. The obtained 2-sulfonylated1,3-diamines can be readily converted to 5-phenylsulfonylated hexahydropyrimidines via removal of the sulfinyl group with MeOH/HCl followed by condensation with aldehydes,and can also undergo radical desulfonation to afford structurally diverse 1,3-diamines using Bu3 SnH as reductant.