The synthesis of 3-substituted 1-methylpyrrolo[1,2-a]pyrazines and 3-substitutedisoquinolines was achieved by the intramolecular cyclisation of 2-acetyl-1-propargylpyrroles and 2-alkynylbenzaldehydes, respectively, in the presence of ammonia under microwave heating. The tandem imination/annulation of 2-alkynylbenzaldehydes was easily accomplished under standard conditions, while TiCl4 was used to
site-selectivity switch has been achieved in the ruthenium-catalyzed C–H arylation reaction of N-acetyl-1,2-dihydroisoquinolines. This metal-mediated switch is antipodal to the previous report on the palladium-mediated C-4 C–H arylation on the same substrate. Mechanistic details reveal interesting aspects of the reaction pathway, and kinetic studies bring out the difference in the modes of C–H activation
Cobalt‐Mediated Decarboxylative/Desilylative C−H Activation/Annulation Reaction: An Efficient Approach to Natural Alkaloids and New Structural Analogues
A Co(II)- mediated decarboxylative/desilylative C−H activation/annulation reaction for the synthesis of 3-arylisoquinoline derivatives has been developed with a good functional group tolerance and wide applications.
NHC-Mediated Stetter-Aldol and Imino-Stetter-Aldol Domino Cyclization to Naphthalen-1(2<i>H</i>)-ones and Isoquinolines
作者:Debabrata Barman、Tanmoy Ghosh、Krishanu Show、Sudipto Debnath、Tapas Ghosh、Dilip K. Maiti
DOI:10.1021/acs.orglett.1c00337
日期:2021.3.19
N-Heterocyclic carbene-catalyzed tandem Stetter-aldol reaction of phthalaldehyde and α,β-unsaturated ketimines has been developed to afford functionalized naphthalen-1(2H)-one derivatives as the formal [4+2] annulation product. Interestingly, the reaction of aldimines led to the formation of isoquinoline derivatives instead of the expected indanone derivatives as a [4+1] annulation product.
A variety of substituted isoquinoline derivatives can be synthesized in moderate yield by a palladium-catalyzed, microwave-assisted MCR starting from o-bromoarylaldehydes, terminal alkynes, and aqueous ammonia.