Organocatalytic alkylation of carbohydrate-containing aldehydes with dihydroquinoline N,O-acetals: Absolute configuration of 1,2-dihydroquinolines
作者:Andrea Menichetti、Francesco Berti、Lorenzo Guazzelli、Lucilla Favero、Sebastiano Di Pietro、Gennaro Pescitelli、Mauro Pineschi
DOI:10.1002/chir.23036
日期:2019.2
dihydroquinolines with aldehydes bearing oxygen functionalities at different positions in a Mannich‐type reaction has been studied. β‐Alkoxy‐aldehyde 1d gave high enantioselectivity, albeit with an inherently poor diastereoselectivity, while the use of α‐alkoxy aldehydes 1c was detrimental also to enantioselectivity. Mannich‐type reactions have been studied for the first time using new chiral carbohydrate‐derived
Experimental and Computational Studies Unraveling the Peculiarity of Enolizable Oxoesters in the Organocatalyzed Mannich-Type Addition to Cyclic N-Acyl Iminium Ions
作者:Andrea Menichetti、Sebastiano Di Pietro、Valeria Di Bussolo、Lucilla Favero、Mauro Pineschi
DOI:10.3390/molecules25081903
日期:——
some organocatalyzed reactions proceeding with a high enantioselectivity. In our experimentation we found that the use of these compounds as the enolizable (nucleophilic) component in organocatalyzed Mannich-type reactions using in situ-generated cyclicN-acyliminiumions gave low diastereoselectivity and low to moderate values of enantioselectivity. This significant drop of facial selectivity with respect
Enantioselective, Nickel-Catalyzed Suzuki Cross-Coupling of Quinolinium Ions
作者:Jason D. Shields、Derek T. Ahneman、Thomas J. A. Graham、Abigail G. Doyle
DOI:10.1021/ol4031364
日期:2014.1.3
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.
Enantioselective Boronate Additions to <i>N</i>-Acyl Quinoliniums Catalyzed by Tartaric Acid
作者:Tomohiro Kodama、Philip N. Moquist、Scott E. Schaus
DOI:10.1021/ol2028702
日期:2011.12.2
Tartaric acid catalyzes the asymmetric addition of vinylboronates to N-acyl quinoliniums, affording highly enantioenriched dihydroquinolines. The catalyst serves to activate the boronate through a ligand-exchange reaction and generates the N-acyl quinolinium in situ from the stable quinoline-derived N,O-acetal.
A highly enantioselective Mannich reaction of aldehydes with cyclic N-acyliminium ions by synergistic catalysis
A novel enantioselective synthesis of carbamoyl isoquinoline and tetrahydropyridine derivatives is accomplished using matched combinations of Lewis or Bronsted acids and secondary amine organocatalysts.