Synthesis of 4,5,8-eicosatrienoic acids

Patterson, John W.; Pfister, Jürg R.; Wagner, Paul; Murthy, Devangachinta

doi:10.1021/jo00163a030

Cited by 9 publications

(6 citation statements)

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“…The filtrate was dried (MgSO 4 ) and concentrated under reduced pressure. Flash chromatography, eluting with light petroleum gave the title compound 15 ( (22).…”

Section: Methyl (Z)-5-tert-butyldimethylsilyloxy-3-(tributylstannyl)pmentioning

confidence: 99%

An approach to the C(10)–C(16) fragment of the bryostatins: stereoselective exocyclic double-bond formation by vinyl radical cyclization

Maguire¹,

Munt²,

Thomas³

1998

J. Chem. Soc., Perkin Trans. 1

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On treatment with tributyltin hydride, the vinyl bromide 11 and the vinyl iodide 26 cyclize to give mixtures of the (E)-and (Z)-4-(alkoxycarbonylmethylene)tetrahydropyrans 12/13 and 27/28 in which the (E)-isomers 12 and 27 are the major components accounting for 80% of the products. Addition of triphenyltin hydride to the alkyne 34 similarly initiates cyclization giving a mixture of products 35-37, the composition of the mixture depending upon the concentration of the tin hydride. These results are consistent with faster cyclization of the (Z)-vinyl radical with kinetic formation of five-membered ring containing products which are either trapped by hydrogen transfer from the tin hydride or which rearrange to form a 4-methylenetetrahydropyran. This chemistry was applied to prepare the cis-2,6-disubstituted 4-(methoxycarbonylmethylene)tetrahydropyran 50 which may be useful for the introduction of the C(10)-C(16) fragment into the bryostatins. Cyclization of the p-methoxybenzyl protected vinyl iodide 58 is less stereoselective, perhaps because of intramolecular hydrogen transfer from the p-methoxybenzyl group.The bryostatins, e.g. bryostatin 7 1, comprise an important group of macrolides which are isolated from invertebrate filter feeders including Bugula neritina and which display potent antitumour activity. 1 The total synthesis of the bryostatins is of considerable interest at present because of the potential of these compounds as chemotherapeutic reagents with a need for a better understanding of their structure-activity relationships. To date one total synthesis of a bryostatin has been described 2 together with several reports of approaches to the synthesis of various fragments. 3-5

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“…The filtrate was dried (MgSO 4 ) and concentrated under reduced pressure. Flash chromatography, eluting with light petroleum gave the title compound 15 ( (22).…”

Section: Methyl (Z)-5-tert-butyldimethylsilyloxy-3-(tributylstannyl)pmentioning

confidence: 99%

An approach to the C(10)–C(16) fragment of the bryostatins: stereoselective exocyclic double-bond formation by vinyl radical cyclization

Maguire¹,

Munt²,

Thomas³

1998

J. Chem. Soc., Perkin Trans. 1

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“…In a similar fashion, the sphingadienine 4 was also prepared through the S N 2‘-type homoallylic coupling reaction between dimesylate 7 and the allylic copper reagent derived from thioether 22 (Scheme 6). Phenylsulfenation of the alcohol 21 with phenyl thiocyanate and tri- n -butylphosphine at THF gave thioether 22 in 95% yield. Metalation of 22 with n -butyllithium and further transmetalation with stoichiometric amount of CuCN·2LiCl provided the thioether-stabilized allylic copper reagent, to which the dimesylate 7 was added to give the S N 2‘ homoallylic coupling product 23 in 94% yield.…”

Section: Resultsmentioning

confidence: 99%

“…Flash column chromatography was performed on silica (10-40 µm) using a mixture of petroleum ether and ethyl acetate as the eluent. Compounds 7 10c and 21 23 were prepared according to published procedures. (2R,3R,4E,8E)-1,3-Di-O-benzyl-9-methyl-2-O-methylsulfonyl-7-(phenylthio)-4,8-octadecadiene-1,2,3-triol (16).…”

Section: Methodsmentioning

confidence: 99%

General and Efficient Syntheses of C₁₈-4,8-Sphingadienines via S_N2‘-Type Homoallylic Coupling Reactions Mediated by Thioether-Stabilized Copper Reagents

Wang

Jiang

et al. 2000

J. Org. Chem.

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The stereoselective syntheses of C(18)-4,8-sphingadienines 3 and 4 as analogues of sphingosine 1 are described. The key step in these syntheses involved a novel S(N)2'-type homoallylic coupling reaction between the corresponding thioether-stabilized allylic copper reagents and the allylic mesylate 7. The thioether-stabilized allylic copper reagents were easily prepared and retained the configuration of their double bond during the coupling reactions, thus overcoming the problem of isomerization which was normally associated with the use of allylic organometallic reagents in such applications.

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“…The readily available chloro-lactone (1 6 I), after conversion into the corresponding acetal-ester (1 62), was transformed (via azide displacement and hydrogenation) into the lactam (163). This was subsequently converted into HOE 892 (1 64), which is equipotent with PGI, as an inhibitor of aggregation of platelets, but is approximately one-tenth as active as a vasodilator.…”

Section: R'oimentioning

confidence: 99%

Prostaglandins, thromboxanes, leukotrienes, and related arachidonic acid metabolites

Hart¹

1988

Nat. Prod. Rep.

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Synthesis of 4,5,8-eicosatrienoic acids

Cited by 9 publications

References 0 publications

An approach to the C(10)–C(16) fragment of the bryostatins: stereoselective exocyclic double-bond formation by vinyl radical cyclization

An approach to the C(10)–C(16) fragment of the bryostatins: stereoselective exocyclic double-bond formation by vinyl radical cyclization

General and Efficient Syntheses of C₁₈-4,8-Sphingadienines via S_N2‘-Type Homoallylic Coupling Reactions Mediated by Thioether-Stabilized Copper Reagents

Prostaglandins, thromboxanes, leukotrienes, and related arachidonic acid metabolites

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Synthesis of 4,5,8-eicosatrienoic acids

Cited by 9 publications

References 0 publications

An approach to the C(10)–C(16) fragment of the bryostatins: stereoselective exocyclic double-bond formation by vinyl radical cyclization

An approach to the C(10)–C(16) fragment of the bryostatins: stereoselective exocyclic double-bond formation by vinyl radical cyclization

General and Efficient Syntheses of C18-4,8-Sphingadienines via SN2‘-Type Homoallylic Coupling Reactions Mediated by Thioether-Stabilized Copper Reagents

Prostaglandins, thromboxanes, leukotrienes, and related arachidonic acid metabolites

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General and Efficient Syntheses of C₁₈-4,8-Sphingadienines via S_N2‘-Type Homoallylic Coupling Reactions Mediated by Thioether-Stabilized Copper Reagents