The reaction of an aromatic heterocycle with a proton is called a protonation. One of articles about this theory is 《Chiral Catalyst Controlled Diastereoselection and Regioselection in Intramolecular Carbon-Hydrogen Insertion Reactions of Diazoacetates》. Authors are Doyle, Michael P.; Kalinin, Alexey V.; Ene, Doina G..The article about the compound:Dirhodium(II) tetrakis(caprolactam)cas:138984-26-6,SMILESS:C12=O[Rh+2]3(O=C4[N-]5CCCCC4)([N-]6C(CCCCC6)=O7)[N-](CCCCC8)C8=O[Rh+2]357[N-]1CCCCC2).Synthetic Route of C24H40N4O4Rh2. Through the article, more information about this compound (cas:138984-26-6) is conveyed.
Individual enantiomers of substituted cyclohexyl diazoacetates or 2-octyl diazoacetates matched with a configurationally suitable chiral dirhodium(II) carboxamidate catalyst provide an effective methodol. for the synthesis of lactones with exceptional diastereo- and regiocontrol. Enantiomerically pure (1S,2R)-cis-2-methylcyclohexyl diazoacetate forms the all-cis-(1R,5R,9R)-9-methyl-2-oxabicyclo[4.3.0]nonan-3-one with complete diastereocontrol in reactions catalyzed by dirhodium(II) tetrakis[methyl 1-(3-phenylpropanoyl)-2-oxoimidazolidine-4(R)-carboxylate], Rh2(4(S)-MPPIM)4, but the configurational mismatch results in a mixture of products. The same diazoacetate produces (1S,5R)-5-methyl-2-oxabicyclo[4.3.0]nonan-3-one with virtually complete selectivity by catalysis with dirhodium(II) tetrakis[methyl 2-oxopyrrolidine-5(S)-carboxylate], Rh2(5(S)-MEPY)4. Similarly high stereo- and regiocontrol is also achieved with enantiomerically pure trans-2-methylcyclohexyl diazoacetates. Product control from insertion reactions of d- or l-menthyl diazoacetate and (+)-neomenthyl diazoacetate from the configurational match with dirhodium(II) catalyst results in the formation of one C-H insertion product in high yield. The exceedingly high product diastereoselection observed in these reactions is consistent with virtually exclusive insertion into equatorial C-H bonds. The catalyst-dependent selective formation of a cis-disubstituted γ-butyrolactone or a β-lactone from 2-octyl diazoacetate has been achieved. Control of product diastereoselectivity and regioselectivity in C-H insertion reactions is explained by conformational suitability in configurational match/mismatch of catalyst and carbene.
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Reference:
Highly efficient and robust molecular ruthenium catalysts for water oxidation,
Catalysts | Special Issue : Ruthenium Catalysts – MDPI