142612-71-3Relevant academic research and scientific papers
The Nafion-H Catalysed Cyclization of α-Carbomethoxy-α-Diazoacetanilides. Synthesis of 3-Unsubstituted-2-Indolinones.
Wee, Andrew G.,Liu, Baosheng
, p. 609 - 626 (2007/10/02)
Diazoanilides of type 4 were found to undergo Nafion-H catalysed cyclization onto the aromatic ring and concomitant decarboxylation, under optimal conditions, to give 3-unsubstituted 2-indolinones 5 in moderate yields.Diazoanilides that possess electron-donating substituents in the aromatic moiety gave higher yields of 5 and, in one case, the presence of an electron-withdrawing group in the aromatic moiety did not impede the cyclization.In the case of the diazoanilides that possess a N-butenyl group, preferential 1,3-dipolar cycloaddition of the diazo unit onto the butenyl double bond occurred to give an unstable 1-pyrazoline which was converted, by loss of nitrogen accompanied by hydrogen migration, to dihydro-2-pyridinone derivatives.It was also found that substituents ortho to the amido group and/or the site of cyclization sterically retarded the cyclization.
Dirhodium Tetraacetate Catalyzed Carbon-Hydrogen Insertion Reaction in N-Substituted α-Carbomethoxy-α-diazoacetanilides and Structural Analogues. Substituent and Conformational Effects
Wee, Andrew G. H.,Liu, Baosheng,Zhang, Lin
, p. 4404 - 4414 (2007/10/02)
A series of acyclic α-carbomethoxy-α-diazoacetanilides with different N-substituents, 5a-k, was prepared and the rhodium(II) acetate catalyzed reaction studied.It was found that the rhodium carbenoid reaction with these compounds occurred only at the N-substituent; when the N-substituent is a propargyl group, rhodium carbenoid addition to the triple bond is favored, resulting, ultimately, in the formation of a bicyclic furan derivative 8.With an N-(tert-butyloxycarbonyl)methyl substituent, interception of the rhodium carbenoid by the ester carbonyl oxygen occurred preferentially to give, eventually, 1,4-oxazine derivatives 9 and 9'.For N'-alkyl substituents, rhodium carbenoid carbon-hydrogen (C-H) insertion into the alkyl group to give the 2-azetidinone and/or 2-pyrrolidinone derivatives was observed.The chemoselectivity of the rhodium carbenoid C-H insertion can be altered by the use of the α-acetyl and α-phenylsulfonyl substituents.In these cases, exclusive C-H insertion at the N-aryl moiety resulted to give 2(3H)-indolinone products.However, the α-substituent effect on the chemoselectivity of the insertion reaction is easily overridden by conformational effects about the amide N-C(O) bond as revealed by the insertion reaction of the conformationally rigid compounds 20a-c.The α-substituent effects are reestablished when conformational rigidity is removed, as exemplified by the rhodium carbenoid insertion reactions of compounds 29a, b.
