Enantioselective, Nickel-Catalyzed Suzuki Cross-Coupling of Quinolinium Ions
摘要:
Quinolinium ions are engaged in an asymmetric, Ni-catalyzed Suzuki cross-coupling to yield 2-aryl- and 2-heteroaryl-1,2-dihydroquinolines. Key to the development of this method is the use of a Ni(II) precatalyst that activates without the need for strong reductants or high temperatures. The Ni-iminium activation mode is demonstrated as an exceptionally mild pathway to generate enantioenriched products from racemic starting materials.
Derivatives of α,α,α′,α′-Tetraaryl-2,2-dimethyl-1,3-dioxolan-4,5-dimethanol (TADDOL) containing nitrogen, sulfur, and phosphorus atoms. New ligands and auxiliaries for enantioselective reactions.
作者:Dieter Seebach、Michiya Hayakawa、Jun-ichi Sakaki、W.Bernd Schweizer
DOI:10.1016/s0040-4020(01)80529-9
日期:1993.2
(5c–5f), as well as a bis(trifluoroacetamide) (5g). Cyclization of the aminoalcohol (4c) produces a bicyclic system (7), containing a pyrrolidine ring (structure determination by X-ray diffraction). - The new chiral compounds containingnitrogen and phosphorusatoms might be useful ligands and auxiliaries for enantioselective syntheses.
been found to occur with 0.5% copper(II) triflate and 1% chiralphosphite. Cyclic phosphites derived from TADDOL gave excellent to moderate enantiomeric excesses. The nature of the exocyclic substituent of the dioxaphospholane ring is important, but the chiral induction is imposed by the TADDOL framework. Syntheses of all the TADDOL ligands are described.