Rhodium-Catalyzed Stereospecific C?H Amination for the Construction of Spiroaminal Cores: Reactivity Difference between Nitrenoid and Carbenoid Species against Amide Functionality
Metal nitrenoids and metal carbenoids exhibit similar reactivity for insertion into a C?H bond and a C=C double bond. These reactions have attracted the attention of organic chemists due to their unusual bond-forming ability, but the reactivity difference between these chemical species has not been studied. In this paper, we examined the reactivity difference using the corresponding Rh nitrenoid and Rh carbenoid precursors. The Rh nitrenoid inserted into an intramolecular C(sp3)?H bond adjacent to an amide nitrogen, affording functionalized spiroaminals that are ubiquitous in natural products, while the Rh carbenoid inserted into an amide C?N bond. The totally different reactivity was rationalized by the relatively low energy barrier for the C?H insertion reaction of the Rh nitrenoid. Computational analysis suggests that the origin of the discrepancy is the electrophilicity of the coordinating atoms to the Rh complex.
Kono, Masato,Harada, Shingo,Nemoto, Tetsuhiro
p. 7428 - 7432
(2017/06/06)
New synthesis and application of 3-substituted prolinols
Carbon skeleton of polysubstituted pyroglutamates with three contiguous asymmetric centers was built up in one base-induced coupling/cyclization reaction of α-sulfonylacetamide with 2-bromo-2-propenoates. A simple transformation to 3-substituted prolinols
2-R2 -R4 -substituted-3-R3 -CO-1-[(C-attached-N-herteryl)-(Alk)n ]-1H-indoles useful as analgesic, anti-rheumatic, anti-inflammatory or anti-glaucoma agents.
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(2008/06/13)
5-Substituted 1-(4-(1-pyrrolidinyl)-2-butynyl)-2-pyrrolidinones, pharmaceutical compositions and use
There are disclosed compounds of the formula STR1 where R1 is loweralkoxycarbonyl, --CH2 OH or --CONR3 R4, R3 and R4 being independently hydrogen, loweralkyl or arylloweralkyl; and R2
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(2008/06/13)
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