[2,3]-Wittig rearrangement approach to iminosugar C-glycosides: 5-epi-ethylfagomine, 2-epi-5-deoxyadenophorine and formal synthesis of indolizidine 167B and 209D

Chandrasekhar, B.; Rao, J. Prasada; Rao, B. Venkateswara; Naresh, P.

doi:10.1016/j.tetlet.2011.08.084

Cited by 21 publications

(5 citation statements)

References 79 publications

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“…Consequently, we do not discuss these numerous reactions further except to state that a number of groups have found uses for this reaction in complex molecule and natural product syntheses. 207,208,386,387,388,389,390,391 …”

Section: Hydrogenation and Isomerizationmentioning

confidence: 99%

“…However, later work revealed that these conditions generate cobalt boride and hydrogen gas in situ, although the mechanism of alkene/alkyne reduction with this heterogeneration mixture remains unclear. Consequently, we do not discuss these numerous reactions further except to state that a number of groups have found uses for this reaction in complex molecule and natural product syntheses. ,,− …”

Section: Hydrogenation and Isomerizationmentioning

confidence: 99%

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Mn-, Fe-, and Co-Catalyzed Radical Hydrofunctionalizations of Olefins

et al. 2016

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Cofactor-mimetic aerobic oxidation has conceptually merged with catalysis of syngas reactions to form a wide range of Markovnikov-selective olefin radical hydrofunctionalizations. We cover the development of the field and review contributions to reaction invention, mechanism and application to complex molecule synthesis. We also provide a mechanistic framework for understanding this compendium of radical reactions.

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Section: Hydrogenation and Isomerizationmentioning

confidence: 99%

Section: Hydrogenation and Isomerizationmentioning

confidence: 99%

Mn-, Fe-, and Co-Catalyzed Radical Hydrofunctionalizations of Olefins

et al. 2016

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“…Application of the developed method for the synthesis of (±)-indolizidine 167B, a natural product isolated from the skin of the frog Dendrobates speciosus, − was examined next (Scheme ). − Reaction of the thioiminium 1 with the organocopper reagent derived from the protected bromoketone 20 , easily prepared from commercial 4-bromobutanoyl chloride in two steps, , afforded the desired 2-substituted pyrrolidine 21 in 80% yield. Remarkably, the use of an organocopper species derived from an organomagnesium reagent is fully compatible with our reaction sequence.…”

Section: Resultsmentioning

confidence: 99%

Reductive Alkylation of Tertiary Lactams via Addition of Organocopper (RCu) Reagents to Thioiminium Ions

et al. 2017

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A simple procedure for the conversion of tertiary lactams to 2-monoalkylated cyclic amines is described. The reaction sequence involves conversion of a lactam to a thioiminium ion followed by reaction with an organocopper (RCu) reagent and final reduction with triacetoxyborohydride. The reaction is high yielding and shows an excellent functional group tolerance. Its utility is demonstrated by a rapid synthesis of indolizidine 167B. The excellent chemoselectivity of the process, where only monoalkylation products are formed, is rationalized by a mechanism involving the formation of a transient enamine.

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“…Nearly all these naturally-occurring iminosugars, as well as the majority of synthetic azapyranose sugars, elicit some sort of biological response [ 6 ]. Although great efforts have been made and numerous synthetic procedures have been developed for the synthesis of iminosugars [ 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 ], efficient methods for the rapid generation of azapyranoses with the structural diversity necessary for in-depth structure-activity studies are still lacking. Due to the versatile reactivities of the nitrone functionality, synthetic methods based on sugar-derived cyclic nitrones have emerged as a potentially powerful strategy for the diversity-oriented synthesis of iminosugars among the existing approaches [ 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 ].…”

Section: Introductionmentioning

confidence: 99%