Enantioselective Rhodium-Catalyzed Addition of Arylboroxines to N-Unprotected Ketimines: Efficient Synthesis of Cipargamin
Highly enantioselective rhodium-catalyzed addition of arylboroxines to 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.
Enantioselective Friedel–Crafts Alkylation Reaction of Heteroarenes with N-Unprotected Trifluoromethyl Ketimines by Means of Chiral Phosphoric Acid
An enantioselective Friedel–Crafts alkylation reaction of pyrroles and indoles with N-unprotected trifluoromethyl ketimines by use of chiral phosphoric acid provided α-trifluoromethylated primary amines bearing chiral tetrasubstituted carbon centers in high yields and with high to excellent enantioselectivities. The present reaction is unique to N-unprotected trifluoromethyl ketimines. No reaction took place with N-p-methoxyphenyl (PMP)-substituted ketimine. Corresponding α-trifluoromethylated amines were transformed without loss of enantioselectivity.
Tertiary amine compound, bisphosphine ligand, and intermediate and preparation method of tertiary amine compound
The invention discloses a tertiary amine compound, a bisphosphine ligand, and an intermediate and a preparation method of the tertiary amine compound, and provides a tertiary amine compound preparation method, which comprises: under the protection of a ga
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Paragraph 0232; 0236-0239; 0240; 0283-0285
(2019/11/20)
Direct access to: N -unprotected tetrasubstituted propargylamines via direct catalytic alkynylation of N -unprotected trifluoromethyl ketimines
Direct catalytic alkynylation of N-unprotected trifluoromethyl ketimines is reported for the first time. A combination of catalytic amounts of diethylzinc and carboxylic acids promoted the reactions under proton-transfer conditions, allowing an unprecedented direct access to N-unprotected α-tetrasubstituted primary amines without additional deprotection steps.