1,5-Hydrogen transfers from carbon to N-tributyltin substituted nitrogen

Kim, Sunggak; Yeon, Kyu Man; Yoon, Kwang Sub

doi:10.1016/s0040-4039(97)00779-x

Cited by 43 publications

(19 citation statements)

References 28 publications

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“…Kim and co-workers generated N-radicals by combination of alkyl azides and Bu 3 Sn • , followed by loss of N 2 . 51 The resultant, Sn-stabilized N-radical effectively performs a 1,5-HAT to yield the δ C-radical, which is then trapped by Bu 3 SnD affording selective δ-deuteration. Recently, metal-catalyzed variants have also been developed for conversion of azides into nitrenoids.…”

Section: Scheme 5 Triiodide Strategy For δ C-h Amination Of Methylenesmentioning

confidence: 99%

Remote C–H Functionalization via Selective Hydrogen Atom Transfer

2018

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The selective functionalization of remote C-H bonds via intramolecular hydrogen atom transfer (HAT) is transformative for organic synthesis. This radical-mediated strategy provides access to novel reactivity that is complementary to closed-shell pathways. As modern methods for mild generation of radicals are continually developed, inherent selectivity paradigms of HAT mechanisms offer unparalleled opportunities for developing new strategies for C-H functionalization. This review outlines the history, recent advances, and mechanistic underpinnings of intramolecular HAT as a guide to addressing ongoing challenges in this arena.

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Section: Scheme 5 Triiodide Strategy For δ C-h Amination Of Methylenesmentioning

confidence: 99%

Remote C–H Functionalization via Selective Hydrogen Atom Transfer

2018

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“…Such radicals give also effi cient 1,5 -hydrogen transfers leading to C -centered radicals. 110 A one -atom ring -expansion of α -azidoketones allows to prepare lactams according to Benati (Scheme 42, top). 111 The same reaction can be used for the conversion of α -azidoα -methylacetylacetate to α -aminoacid under radical reduction with Bu 3 SnH (Scheme 8.42 , bottom).…”

Section: Radical Reactions Of Organic Azides With Tributyltin Hydridementioning

confidence: 99%

Schmidt Rearrangement Reactions with Alkyl Azides

Grecian¹,

Aubé

2009

Organic Azides

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The sobriquet ' Schmidt reaction ' refers to a number of related processes in which hydrazoic acid or an alkyl azide reacts with an electrophile. 1 -6 The product obtained will depend on the reaction partner (carboxylic acids generate amines, aldehydes give nitriles and formamides, and ketones provide amides, respectively) but all of these reactions have certain features in common. They are the initial nucleophilic addition of the azide component to an electrophile (usually promoted by acid) eventually followed by a rearrangement step driven by the energetically favorable loss of nitrogen. The classical Schmidt reaction of hydrazoic acid with ketones is generally considered to involve an intermediate dehydration step. 7,8 Despite the diversity of reactions that comprise the Schmidt family, its single most common variant is shown in Scheme 7.1 . This overall process can be regarded as an insertion of NH between the carbonyl and an α alkyl group. 9 The development of this version of the Schmidt reaction predates the experience of anyone working in organic chemistry today (Schmidt ' s original report was in 1924) but the extension of the concept to nucleophilic alkyl azides is a decidedly contemporary development. For example, if one compares the two reactions shown in Scheme 7.2 , it is clear that the direct insertion of an alkyl azide into cyclohexanone allows for the introduction of additional nitrogen atom substitution and, in the case of an alkyl azide tethered to a carbonyl substrate, the possibility of an intramolecular reaction. The goal of this chapter

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“…108 Preparation of cyclic imines via a tin hydride promoted radical cyclization onto an hydrazone is also possible (Scheme 8.41 , bottom). 110 A one -atom ring -expansion of α -azidoketones allows to prepare lactams according to Benati (Scheme 42, top). Such radicals give also effi cient 1,5 -hydrogen transfers leading to C -centered radicals.…”

Section: Radical Reactions Of Organic Azides With Tributyltin Hydridementioning

confidence: 99%

Radical Chemistry with Azides

Jimeno

Renaud

2009

Organic Azides

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Organic azides represent a very interesting class of compounds since they are precursor of a wide range of nitrogen containing organic molecules. 1 Moreover, they possess a unique reactivity pattern orthogonal to many other organic functional groups. This assessment is also true in the fi eld of radical chemistry. For instance, azides can be considered as protected amino groups that are perfectly tolerated in C -C bond forming reactions. This is illustrated by the synthesis of ( − ) -batzelladine D recently disclosed by P.A. Evans. 2 In this synthesis, a pyrrolo[1,2f]pyrimidine is built via a 5exo trig radical cyclization. The two azido substituents present in the molecule are not reduced under the reaction conditions used to run the cyclization (tributyltin hydride and triethylborane in the presence of air at room temperature) (Scheme 8.1 ).The stability of azides in radical reactions is further illustrated by the radical fragmentation of carbohydrate anomeric alkoxyl radicals bearing an azido substituent at position 3 reported by Suarez (Scheme 8.2 ). 3,4 After fragmentation, the 2 -azido -substituted radical is iodinated and no β -fragmentation of the azide is observed.However, under suitable conditions, azides react with a variety of radicals and this is the basis of several useful synthetic procedures for the formation of carbon -nitrogen bonds. For instance, synthesis of azides by radical addition of an azidyl radical to alkenes (Scheme 8.3 a) and by reaction of an alkyl radical with an azidating reagent (Scheme 8.3 b) will be presented. The reduction of azides leading to aminyl radicals (Scheme 8.3 c) and the addition of alkyl radicals to alkyl azides (Scheme 8.3 d) will also be discussed.

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1,5-Hydrogen transfers from carbon to N-tributyltin substituted nitrogen

Cited by 43 publications

References 28 publications

Remote C–H Functionalization via Selective Hydrogen Atom Transfer

Remote C–H Functionalization via Selective Hydrogen Atom Transfer

Schmidt Rearrangement Reactions with Alkyl Azides

Radical Chemistry with Azides

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