Chiral tris(oxazoline)/Cu(ii) catalyzed coupling of terminal alkynes and nitronesElectronic supplementary information (ESI) available: experimental. See http://www.rsc.org/suppdata/cc/b3/b306653c/
Novel chiral iPr-tris(oxazoline)/Cu(ClO4)2 x 6H2O catalyzedcoupling of terminal acetylenes and nitrones to afford cis-disubstituted beta-lactams is described; the choice of base proves essential to both the diastereoselectivity and the enantioselectivity.
描述了新颖的手性iPr-三(恶唑啉)/ Cu(ClO4)2 x 6H2O催化的末端乙炔和硝酮的偶联,得到顺式二取代的β-内酰胺。碱的选择被证明对非对映选择性和对映选择性都是必不可少的。
Enantioselective synthesis of β-lactams via the IndaBox–Cu(II)-catalyzed Kinugasa reaction
The enantioselective Kinugasareaction of nitrones with terminal alkynes in the presence of 20 mol % of IndaBox–Cu(OTf)2 and di-sec-butylamine (1.5 equiv) produced β-lactams with the highest level of enantiomeric excesses among the catalytic enantioselective Kinugasareactions reported so far.
Electrogenerated N-heterocyclic carbene can behave as an organocatalyst in the Staudinger reaction (from imine and acyl chloride) in a very polar solvent, such as an ionic liquid.
Reaction of arylacetylenes with C,N-diarylnitrones using a catalyst system of CuI-dppe (dppe = 1,2-bis(diphenylphosphino)ethane) in the presence of potassium carbonate in DMF predominantly affords the corresponding 1,2,4-triaryl-1-aza- 1-buten-3-ynes in good yields. In contrast, the catalytic reaction using CuI in the presence of an excess amount of pyridine as the ligand gives 1,3,4-triaryl-2-azetidinones as the major products. The reaction with aliphatic terminal alkynes in place of arylacetylenes produces the latter products irrespective of the catalyst system used. Asymmetric induction is also observed in the reaction of phenylacetylene with alpha,N-diphenylnitrone to give 1,2,4-triphenyl-2-azetidinone in the presence of chiral bisoxazoline-type ligands.