Synthesis of Highly Enantiomerically Enriched Amines by Asymmetric Transfer Hydrogenation of N ‐ (tert ‐Butylsulfinyl)Imines

Abstract

4‐Pyridinecarboxaldehyde Dichloromethane 3‐ tert ‐Butyl‐2‐hydroxybenzaldehyde Sodium borohydride Methanol 2‐(1,1‐Dimethylethyl)‐6‐[[[(1 R ,2 R )‐2‐[(4‐pyridinylmethyl)amino]‐cyclohexyl]amino]methyl]‐phenol (1 R ,2 R )‐1,2‐Diaminocyclohexane (1 S )‐1‐(4‐Nitrophenyl)‐2‐nitroethane‐1‐ol Copper acetate Ethanol p ‐Nitrobenzaldehyde Nitromethane

Synthesis of Nitrogenated Heterocycles by Asymmetric Transfer Hydrogenation of N-(tert-Butylsulfinyl)haloimines

“…Encouraged by the excellent results that we had obtained in the synthesis of enantiomerically enriched amines through a ruthenium-catalyzed ATH of sulfinylimines, we decided to try to extend this methodology to the diastereoselective reduction of N -( tert -butylsulfinyl)ketimines 2 bearing halogen atoms that could later act as leaving groups in intramolecular nucleophilic substitution processes that would lead to N -protected saturated heterocycles 4 (Scheme ). Since the sulfinyl group can easily be removed, this sequence would represent an interesting way of preparing nitrogenated heterocyclic compounds.…”

“…In the last years, several of our research activities have focused on diastereoselective processes using enantiomerically pure N -( tert -butylsulfinyl)imines as substrates . We have developed a very effective method for the preparation of highly enantiomerically enriched aromatic and aliphatic amines by ruthenium-catalyzed ATH of N -( tert -butylsulfinyl)ketimines in isopropyl alcohol followed by desulfinylation of the nitrogen atom . Recently, we have used this hydrogen transfer based reduction methodology as a key step to accomplish the synthesis of optically enriched γ-, δ-, and ε-lactams from N -( tert -butylsulfinyl)iminoesters .…”

Transition metal-catalyzed reactions of N-sulfinyl imines

“…The Ru-catalyzed transfer hydrogenation of ketimines 25 using isopropanol as hydrogen source and an amino alcohol as ligand under basic conditions afforded the corresponding chiral sulfinyl amines which were in situ deprotected to the corresponding primary amines 26 [17]. As amino alcohol, initially the indanol derivative 27 was the most efficient as shown in Scheme 9 [18].…”