Synthesis of β-amino-α-trifluoromethyl alcohols and their applications in organic synthesis

Synthesis of Trifluoromethylated Monoterpene Amino Alcohols

For the first time, monoterpene trifluoromethylated β-hydroxy-benzyl-O-oximes were synthesized in 81–95% yields by nucleophilic addition of the Ruppert–Prakash reagent (TMSCF3) to the corresponding β-keto-benzyl-O-oximes based on (+)-nopinone, (−)-verbanone and (+)-camphoroquinone. Trifluoromethylation has been determined to entirely proceed chemo- and stereoselective at the C=O rather than C=N bond. Trifluoromethylated benzyl-O-oximes were reduced to the corresponding α-trifluoromethyl-β-amino alcohols in 82–88% yields. The structure and configuration of the compounds obtained have been established.

A zinc/PyBisulidine catalyzed asymmetric Mannich reaction of N-tosyl imines with 3-acyloxy-2-oxindoles

A Zn-PyBisulidine catalyzed asymmetric Mannich reaction of 3-acyloxy-2-oxindoles has been developed. Various quaternary substituted 3-acyloxy-2-oxindoles bearing vicinal amino alcohol motifs were obtained in good to excellent yields with moderate to excellent dr and excellent enantioselectivities. The utility of this reaction was demonstrated by the easy removal of the acyl group to give C3-hydroxy derivatives and their application as a key skeleton of the ligand for the Ni-catalyzed enantioselective Henry reaction.

Ru-Tethered (R,R)-TsDPEN with DMAB as an efficient catalytic system for high enantioselective one-pot synthesis of chiral β-aminol via asymmetric transfer hydrogenation

This work reflects Ru-tethered-TsDPEN as an active chiral catalyst for one pot selective synthesis of optically active α-substituted alcohols and its derivatives from α-bromo ketones in the presence of dimethylamine borane (DMAB) as the hydrogen source.

Recent applications of chiral N-tert-butanesulfinyl imines, chiral diene ligands and chiral sulfur–olefin ligands in asymmetric synthesis

The highly efficient asymmetric reactions of chiral sulfinyl auxiliary, diene ligands and sulfur–olefin ligands are presented.

Trifluoromethyl syn- or anti-γ-amino alcohols by one-pot solvent-free Mannich-type reactions under temperature control

A highly diastereoselective synthesis of fluorinated syn- or anti-γ-amino alcohols was reported by a simple and environmentally benign methodology. Unexpectedly, a strong influence of the reaction conditions on the facial selective attack was found.

Selective synthesis of cis- and trans-2-(methyl/phenyl)-3-(trifluoromethyl)aziridines and their regio- and stereospecific ring opening

A convenient and stereoselective approach toward cis- and trans-1-alkyl-2-(methyl/phenyl)-3-(trifluoromethyl)aziridines was developed starting from the corresponding α,α,α-trifluoroketones via imination, α-chlorination, and hydride-induced ring closure. The reactivity of these newly synthesized nonactivated α-CF3-aziridines was evaluated by applying N-protonation or N-alkylation to effect regio- and stereospecific aziridine ring opening by oxygen, halogen, sulfur, and nitrogen nucleophiles. Furthermore, nonactivated α-CF3-aziridines were easily transformed into their activated analogues by replacing the N-benzyl protecting group with a N-tosyl group, rendering these α-CF3-aziridines much more susceptible to nucleophilic ring opening.

Convergent, asymmetric synthesis of vicinal amino alcohols via Rh-catalyzed addition of α-amido trifluoroborates to carbonyls

The convergent, asymmetric synthesis of vicinal amino alcohols is achieved by the Rh-catalyzed addition of α-amido trifluoroborates to carbonyl compounds.

Novel synthesis of pseudopeptides bearing a difluoromethyl group by Ugi reaction and desulfanylation

Thirteen difluoromethyl-containing pseudopeptides were synthesized by Ugi reaction using the novel building block 2,2-difluoro-2-(phenylthio)acetic acid (2) as one component, followed by removal of the phenylsulfanyl protecting group in the presence of tributyltin hydride and azobisisobutyronitrile.

Organocatalytic asymmetric Strecker reaction of di- and trifluoromethyl ketoimines. Remarkable fluorine effect

A highly enantioselective Strecker reaction of difluoromethyl and trifluoromethyl ketoimines was developed. Remarkable fluorine effect on the reactivity and selectivity is observed and discussed.