Topic
Intramolecular reaction
About: Intramolecular reaction is a research topic. Over the lifetime, 5015 publications have been published within this topic receiving 138213 citations.
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TL;DR: The reaction of specifically protected anhydroalditols with (diacetoxyiodo)benzene or iodosylbenzenes and iodine is a mild and selective procedure for the synthesis of chiral 6,8-dioxabicyclo[3.2.1]heptane ring systems under neutral conditions.
Abstract: The reaction of specifically protected anhydroalditols with (diacetoxyiodo)benzene or iodosylbenzene and iodine is a mild and selective procedure for the synthesis of chiral 6,8-dioxabicyclo[3.2.1]octane and 2,7-dioxabicyclo[2.2.1]heptane ring systems under neutral conditions. This reaction can be considered to be an intramolecular glycosidation that goes through an intramolecular hydrogen abstraction promoted by an alkoxy radical followed by oxidation of the transient C-radical intermediate to an oxycarbenium ion. This methodology is useful not only for the preparation of chiral synthons but also for the selective oxidation of specific carbons of the carbohydrate skeleton, constituting a good procedure for the synthesis of protected uloses.
74 citations
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TL;DR: Two model studies in support of a total synthesis of the complex polycyclic alkaloid daphnilactone B have been completed to demonstrate the use of a tandem double-intramolecular nitroalkene cycloaddition for the stereocontrolled construction of four of the rings in the core of the natural product.
Abstract: Two model studies in support of a total synthesis of the complex polycyclic alkaloid daphnilactone B have been completed. The objectives of the models studies were to demonstrate the use of a tandem double-intramolecular [4+2]/[3+2] nitroalkene cycloaddition for the stereocontrolled construction of four of the rings in the core of the natural product. The first model study established the ability to create a pyrrolidine ring corresponding to ring A of daphnilactone B through a modification of the dipolarophile and subsequent functional group manipulations. The second model study required the modification of the dienophile in the [4+2] cycloaddition to accommodate the formation of a piperidine ring (ring B of daphnilactone B). Nitroalkene 26 containing a diene as the dienophile served well in the tandem cycloaddition to afford the nitroso acetal 38a in 77% yield. Subsequent functional group manipulations allowed for the high-yielding conversion to the core of daphnilactone B.
74 citations
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TL;DR: In this paper, a mild and efficient methodology for the synthesis of oxygenated carbazoles from diarylamines under non-acidic conditions was developed, based on a palladium-catalyzed, microwave-assisted double C-H bond activation process.
74 citations
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TL;DR: In this article, the reaction of enediyne aldehyde 16 with LiN(SiMe 3 ) 2 leads to intramolecular acetylide cyclization to the epimeric carbinols 17 comprising a deoxyaglycone model for the calicheamicins.
74 citations
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TL;DR: In this article, the combination of 5 with NaB[3,5-C6H3(CF3)2]4 (denoted as NaBArF4) provides a potent catalytic system for both intra-and intermolecular hydroamination of alkynes.
74 citations