Synthesis of 2-aryl-2-trifluoromethyl-1,3-thiazolidin-4-ones and 2-aryl-2-trifluoromethyltetrahydro-4H-1,3-thiazin-4-ones and their oxidation with hydrogen peroxide
摘要:
Reactions of aryl trifluoromethyl ketone imines with 2-sulfanylacetic and 3-sulfanylpropanoic acids afforded 2-aryl-2-trifluoromethyl-1,3-thiazolidin-4-ones and 2-aryl-2-trifluoromethyltetrahydro-4H-1,3-thiazin-4-ones, respectively. Their subsequent oxidation with hydrogen peroxide gave the corresponding 2-aryl-2-trifluoromethyl-1,3-thiazolidin-4-one 1-oxides and 2-aryl-2-trifluoromethyltetrahydro-4H-1,3-thiazin-4-one 1-oxides and 1,1-dioxides.
Enantioselective Synthesis of 2‐Substituted Indoles Bearing Trifluoromethyl Moiety by the Friedel‐Crafts Alkylation Reaction of 4,7‐Dihydroindole with
<i>N</i>
−H Trifluoromethyl Ketimines
The Friedel‐Crafts alkylation reaction of 4,7‐dihydroindole with N‐unprotected trifluoromethyl ketimines by means of chiral phosphoric acid and the subsequent oxidation with DDQ afforded chiral 2‐indolylmethylamines bearing a trifluoromethyl moiety in good to high yields with excellent enantioselectivities under one‐pot conditions. The adduct was transformed without loss of enantioselectivity and the
N-unprotected ketimines is realized for the first time by employing chiral BIBOP-type ligands with a Rh loading as low as 1 mol %. A range of chiral α-trifluoromethyl-α,α-diaryl α-tertiary amines or 3-amino-3-aryloxindoles were formed with excellent ee values and yields by employing either WingPhos or PFBO-BIBOP as the ligand. The method has enabled an efficient enantioselective synthesis of cipargamin
The first enantioselective hydrophosphonylation of ketimines with phosphine oxides was developed. The reaction of unprotected ketimines with phosphine oxides using a bis(imidazoline)-phosphoric acid catalyst gave chiral α-quaternary aminophosphorous compounds having a primary amino group in excellent yields and enantioselectivities. Based on experimental results and DFT calculation, transition states