A directed chiral synthesis of amino acids from boronic esters

Matteson, Donald S.; Beedle, Ellen C.

doi:10.1016/s0040-4039(00)96547-x

Cited by 74 publications

(42 citation statements)

References 17 publications

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“…11,12 For the carboxylic group, in particular, we envisaged that protection as a tert-butyl ester would be appropriate, owing to its well-known resistance to strongly basic environments such as those that were planned to be encountered in all the subsequent steps of our synthetic voyage, homologations included, 11,13,14 and because of great ease of deprotection.…”

Section: Unitmentioning

confidence: 99%

Enantioselective total synthesis of (−)-microcarpalide

et al. 2005

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Section: Unitmentioning

confidence: 99%

Enantioselective total synthesis of (−)-microcarpalide

et al. 2005

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“…After working with essentially nonvolatile pinanediol boronic esters, it is easy to forget that rapidly evaporating a large amount of ether from a small amount of a moderately volatile pheromone may carry away much of the pheromone, just as blowing a stream of air across it would. tert-Butyl lithioacetate reacts with pinacol (iodomethyl)-or (bromomethyl)boronate to provide the 3-borylpropionate 89 [51,52]. Conversion into asymmetric α-chloro boronic ester 90 followed by substitution with a lithioalkyne and standard further transformations has provided a short and simple synthesis of the Japanese beetle pheromone (japonilure, 91) in high stereopurity (Scheme 8.19) [52].…”

Section: Carbonyl Substituentsmentioning

confidence: 99%

“…Once this information had been obtained, a simple asymmetric synthesis of amino acids (130) followed (Scheme 8.30) [67]. Reactions with azide ion were sluggish, and (α-bromoalkyl)boronic esters (126) were preferred.…”

Section: Azido Substituentsmentioning

confidence: 99%

(α‐Haloalkyl)boronic Esters in Asymmetric Synthesis

Matteson¹

2005

Boronic Acids

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The utility of (α-haloalkyl)boronic esters in asymmetric synthesis results from a unique combination of several features of their chemistry. A wide variety of products can be obtained in very high stereopurity, and the reactions are compatible with a considerable variety of functional substituents, provided that OH and NH groups are masked. Stereospecific displacement of halide from an (α-haloalkyl)boronic ester with a nucleophile yields an asymmetric boronic ester, which can either be converted stereospecifically into another product such as an alcohol or put into another cycle of reaction with (dihalomethyl)lithium to install additional stereocenters. The general synthetic utility of these boronic esters can best be understood from a detailed outline of the general processes involved.The most useful biological applications of these compounds have included the synthesis of some asymmetric insect pheromones in very high stereopurity, described in Sections 8.3.1 and 8.3.3, and the proteasome inhibitor "Velcade™" (bortezomib) developed by Millennium Pharmaceuticals and recently approved by the United States FDA as well as the European Union for treatment of relapsed and refractory multiple myeloma, Section 8.3.6. General Description of (α-Haloalkyl)boronic Ester Chemistry A Brief History of Boronic Ester ChemistryFirst, simple achiral boronic acids and esters are readily available from various sources (Chapter 1). The first synthesis from an organozinc reagent preceded general acceptance of Avogadro's hypothesis [1], and was superseded nearly a century ago by the now standard preparation from Grignard reagents [2,3]. Hydroboration has Boronic Acids. Edited by Dennis G. Hall

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“…We have previously reported [2-(benzyloxy)-1-chloroethyl]boronic esters [3,11,12]. Earlier attempts to convert these to [2-(benzyloxy)-1-[bis(trimethylsilyl)amino]ethyl]boronic esters and react them with (dichloromethyl)lithium failed.…”

Section: Protected [1-amino-2-(trityloxy)ethyl]boronic Estersmentioning

confidence: 99%

“…However, previous attempts to utilize ␣-bis-(trimethylsilyl)amino boronic esters in this process have yielded moisture-sensitive products that could not be purified. Instead, ␣-azido boronic esters were used in asymmetric syntheses of b-amino alcohols [2] and ␣-amino acids [3]. ␣-Amino boronic esters that contain an NH group are unstable toward deboronation [4], and silyl-protected amino boronic esters remain the intermediates of choice for most preparations of ␣-amido boronic acids, several of which are potent serine protease inhibitors [5].…”

Section: Introductionmentioning

confidence: 99%