Journal ArticleDOI
Rhodium(II)-catalyzed aziridination of allyl-substituted sulfonamides and carbamates.
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TLDR
The expected aziridine was not observed, but rather simultaneous spirocyclization of C(3) and stereoselective syn-acylation at C(2) occurred to give compound 41, whose structure was unequivocally established by an X-ray crystallographic study.Abstract:
Several unsaturated sulfonamides underwent intramolecular aziridination when treated with PhI(OAc)(2), MgO, and catalytic Rh(2)(OAc)(4) to give bicyclic aziridines in excellent yield. Treatment of the resulting azabicyclic sulfonamides in methanol in the presence of p-TsOH resulted in exclusive opening of the aziridine ring at the most substituted position affording six- and seven-membered ring products in high yield. In contrast, the intramolecular aziridination of several cycloalkenyl-substituted carbamates did not require a Rh(II) catalyst and proceeded via an iminoiodinane intermediate. The resulting tricyclic aziridines underwent ring opening when treated with various nucleophiles to give anti-derived products as expected for nucleophilic attack at the three-membered ring. The iodine(III)-mediated reaction of a 3-indolyl-substituted carbamate, however, required a Rh(II) catalyst. The expected aziridine was not observed, but rather simultaneous spirocyclization of C(3) and stereoselective syn-acylation at C(2) occurred to give compound 41, whose structure was unequivocally established by an X-ray crystallographic study. The reaction proceeds in a stepwise manner via a metal-free zwitterionic intermediate which is attacked by a nucleophilic reagent on the same side of the amide anion. Related reactions occurred with both a 2-indolyl- and 3-benzofuranyl-substituted carbamate but with lower stereoselectivity.read more
Citations
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Catalytic C-H amination: recent progress and future directions.
TL;DR: The careful design of reagents and catalysts now provides efficient conditions for exquisitely selective intramolecular as well as intermolecular nitrene C-H insertion and opens new opportunities complementary to those offered by nitrenes.
Journal ArticleDOI
Nitrene Chemistry in Organic Synthesis: Still in Its Infancy?
TL;DR: It is suggested that synthetic nitrene chemistry is maturing with a wider scope not limited to these two reactions, as practical metal-catalyzed protocols for the preparation of amines through either the aziridination of alkenes or the C-H amination of alkanes are available.
Journal ArticleDOI
Advances in dearomatization strategies of indoles
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Recent developments in methodology for the direct oxyamination of olefins.
TL;DR: The purpose of this review is to give the reader a tour of the methods that have emerged in the last few years so one can appreciate the myriad of different metals and reagents that can accomplish the oxyamination of alkenes.
Journal ArticleDOI
Imido transfer from bis(imido)ruthenium(VI) porphyrins to hydrocarbons: effect of imido substituents, C-H bond dissociation energies, and Ru(VI/V) reduction potentials.
TL;DR: A linear correlation was observed between log k' (k' is the k2 value divided by the number of reactive hydrogens) and BDE andbetween log k2 and E(1/2)(Ru(VI/V); the linearity in the former case supports a H-atom abstraction mechanism.
References
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Journal ArticleDOI
Recent advances in olefin metathesis and its application in organic synthesis
Robert H. Grubbs,Sukbok Chang +1 more
TL;DR: In this paper, a review of recent advances in olefin metathesis focusing on the areas of ring-closing olefi cation (RCM) and cross-metathesis is presented.
Journal ArticleDOI
1,2-Amino Alcohols and Their Heterocyclic Derivatives as Chiral Auxiliaries in Asymmetric Synthesis
Journal ArticleDOI
Organic Synthesis with .alpha.-Diazo Carbonyl Compounds
Tao Ye,M. Anthony McKervey +1 more
Journal ArticleDOI
Chiral Aziridines—Their Synthesis and Use in Stereoselective Transformations
TL;DR: Chiral bisaziridines can be used as ligands for transition metals, and applications in the challenging field of enantioselective catalysis can be envisioned as discussed by the authors.
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