Osmium tetroxide catalyzed hydroxylation of hindered olefins

Ray, Rahul; Matteson, Donald S.

doi:10.1016/s0040-4039(00)71429-8

Cited by 162 publications

(55 citation statements)

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“…Isopropylidenation of 14 yielded 88% of the acetal 15. Initial attempts to obtain the cis-diol 16 by treating 15 with OsO 4 and N-methylmorpholine N-oxide (NMO) in acetone [26] led to several side-products which were not characterized, while dihydroxylation with OsO 4 and trimethylamine N-oxide in t-BuOH/ H 2 O containing traces of pyridine [27] led exclusively to the exo-cis-diol 16 (72%) that was isopropylidenated to the tetracyclic acetal 17 (97%). Hydrogenolytic debenzylation of 17 in the presence of 10% Pd/C at 6 bar H 2 in AcOEt led to the alcohol 18 (90%).…”

mentioning

confidence: 99%

7‐Oxanorbornane and Norbornane Mimics of a Distorted β‐D‐Mannopyranoside: Synthesis and Evaluation as β‐Mannosidase Inhibitors

Buser

Vasella

2005

Helvetica Chimica Acta

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The racemic 7-oxanorbornanyl and norbornanyl aminoalcohols 3, 4, 42, 45, and 46 were synthesized and tested as snail b-mannosidase inhibitors. The amino tetraol 3 was obtained from the known sulfonyl acrylate 9 and furan 10. Esterification provided 11 that underwent an intramolecular Diels-Alder reaction to the 7-oxanorbornene 12. Reduction of 12 to 13, desulfonylation, isopropylidenation, and cis-dihydroxylation gave 16. A second isopropylidenation to 17, followed by debenzylation and a Mitsunobu-Gabriel reaction provided 19 that was deprotected via 20 to 3. Diels-Alder cycloaddition of furfuryl acetate and maleic anhydride to 21, followed by alcoholysis of the anhydride, cis-dihydroxylation, isopropylidenation, and Barton decarboxylation gave the ester 25. Deacetylation to 26 and a Mitsunobu-Gabriel reaction led to 27 that was transformed into the NBoc analogue 29, reduced to the alcohol 30, and deprotected to 4. The 1-aminonorbornane 5 was obtained from Thiele's Acid 31. Diels-Alder cycloaddition of the cyclopentadiene obtained by thermolysis of the diester 32, methanolysis of the resulting anhydride 33, dihydroxylation, isopropylidenation, Barton decarboxylation, and Curtius degradation led to the benzyl carbamate 39 that was reduced to the alcohol 40, transformed into the N-Boc carbamate 41, and deprotected to 5. The alcohol 40 was also transformed into the benzylamine 42, aniline 45, and hydroxylamine 46. Snail b-mannosidase was hardly inhibited by 3, 4, 42, 45, and 46. Only the amino triol 5 proved a stronger inhibitor. The inhibition by 5 depends on the pH value (at pH 3.5: K i = 1900 mM; at pH 4.5: K i = 340 mM; at pH 5.5: K i = 110 mM). The results illustrate the strong dependence of the inhibition by bicyclic mimics upon the precise geometry and orientation of the amino group as determined by the scaffold. It is in keeping with the hypothesis that the reactive conformation imposed by snail b-mannosidase is close to aIntroduction. -The design, synthesis, and study of glycosidase inhibitors continue to attract interest, fuelled by the potential of strong and selective glycosidase inhibitors to act as drugs (e.g., against lysosomal storage disorders such as Gaucher's disease , and their use as tools in the elucidation of the mechanism of action of glycosidases on the basis of structure-activity relations, kinetic studies, and information provided by the structure determination of enzyme-inhibitor complexes [7]. Transition-state analogues promise to be most useful. Their design is based upon existent information about the mechanism of action, and particularly about the transition state of the rate-determining step, while their study may contribute to a more detailed understanding of the mechanisms of action as summarised in several reviews [8] [9]. Partial transition-state mimics may be thought of as being closer to a point of the reaction coordinate that either precedes, or follows the transition state of interest, and there are reasons to hypothesise that those preceding the rate-determining transition s...

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confidence: 99%

7‐Oxanorbornane and Norbornane Mimics of a Distorted β‐D‐Mannopyranoside: Synthesis and Evaluation as β‐Mannosidase Inhibitors

Buser

Vasella

2005

Helvetica Chimica Acta

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“…20 Os dióis (-)-5 e (+)-6 e os demais reagentes são comerciais (Aldrich 21 [(-)-pinanodiol]: A uma solução de tetróxido de ósmio (0,0787 mmol) em terc-butanol (1 mL) foi adicionado (-)-α-pineno 1 (25 mmol), NMO (34 mmol), piridina (2 mL), água (15 mL) e tercbutanol (50 mL). A solução púrpura foi refluxada sob atmosfera de nitrogênio durante 17 h. A seguir, a mistura foi resfriada a 25 o C, tratada com uma solução a 20% de bissulfito de sódio (20 mL) e concentrada a vácuo até total remoção do terc-butanol.…”

Section: Parte Experimetalunclassified

“…O hidróxi-nitrogenado-1,2 (+)-7 foi preparado pela adição nucleofílica de 2-litio-piridina à cetona (+)-10, em THF anidro e a temperatura de -100 o C. De maneira semelhante, ao utilizar a (+)-isopinocanfona 10 com o ânion da picolina em THF a temperatura ambiente levou ao hidróxi-nitrogenado-1,3 (-)-8 (Esquema 2). [21][22][23][24] A seguir foram efetuadas as reações de Reformatsky assimétrica reagindo-se benzaldeído 11 ou as cetonas 12 e 13 (1 mmol) com o reagente de Reformatsky RR (3 mmol; 2-bromoetilacetato de etila e zinco em pó) na presença dos ligantes quirais 4-8 (L*), em refluxo de THF (Esquema 3).…”

Section: Visando O Estudo Da Reação De Reformatsky Assimétrica Iniciunclassified

Monoterpenos di-hidroxilados e hidróxi-nitrogenados 1,2 e 1,3 como ligantes quirais em reação de reformatsky assimétrica

2008

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“…α-Pinene (13) reacts with trimethylamine N-oxide and osmium tetroxide catalyst in the presence of pyridine and water to produce pinanediol (14) (Scheme 8.3) [23,24]. A kinetic study has shown that the reaction is first-order in trimethylamine N-oxide, first-order in osmium tetroxide, and zero-order in α-pinene [25].…”

Section: -Symmetrical Boronic Estersmentioning

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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Osmium tetroxide catalyzed hydroxylation of hindered olefins

Cited by 162 publications

References 9 publications

7‐Oxanorbornane and Norbornane Mimics of a Distorted β‐D‐Mannopyranoside: Synthesis and Evaluation as β‐Mannosidase Inhibitors

7‐Oxanorbornane and Norbornane Mimics of a Distorted β‐D‐Mannopyranoside: Synthesis and Evaluation as β‐Mannosidase Inhibitors

Monoterpenos di-hidroxilados e hidróxi-nitrogenados 1,2 e 1,3 como ligantes quirais em reação de reformatsky assimétrica

(α‐Haloalkyl)boronic Esters in Asymmetric Synthesis

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