@article{DavidCoyEnriqueCucaSefkow2011, author = {David Coy, Ericsson and Enrique Cuca, Luis and Sefkow, Michael}, title = {Pd-NHC catalyzed biaryl coupling by direct C-H Activation-A Novel strategy for the synthesis of dibenzocyclooctane lignans}, series = {Synthetic communications : an international journal for rapid communication of synthetic organic chemistry}, volume = {41}, journal = {Synthetic communications : an international journal for rapid communication of synthetic organic chemistry}, number = {1}, publisher = {Taylor \& Francis Group}, address = {Philadelphia}, issn = {0039-7911}, doi = {10.1080/00397910903531755}, pages = {41 -- 51}, year = {2011}, abstract = {Cross-coupling reactions, such as Buchwald-Hartwig arylamination and direct intramolecular biaryl coupling by C-H activation, were carried out using various Palladium-N-heterocyclic carbenes (Pd-NHC) as catalysts. The yields were good to excellent. The latter strategy was adopted to transform two dibenzylbutane lignans, isolated from the leaves of Ocotea macrophylla (Lauraceae), into the corresponding dibenzocyclooctane lignans in good overall yields. Supplemental materials are available for this article. Go to the publisher's online edition of Synthetic Communications (R) to view the free supplemental file.}, language = {en} } @article{CoyBarreraCucaSuarezSefkowetal.2012, author = {Coy-Barrera, Ericsson D. and Cuca-Suarez, Luis E. and Sefkow, Michael and Schilde, Uwe}, title = {Cinerin C: a macrophyllin-type bicyclo[3.2.1]octane neolignan from Pleurothyrium cinereum (Lauraceae)}, series = {Acta crystallographica : Section C, Crystal structure communications}, volume = {68}, journal = {Acta crystallographica : Section C, Crystal structure communications}, number = {2}, publisher = {Wiley-Blackwell}, address = {Hoboken}, issn = {0108-2701}, doi = {10.1107/S0108270112030946}, pages = {O320 -- +}, year = {2012}, abstract = {The structure of naturally-occurring cinerin C [systematic name: (7S,8R,3'R,4'S,5'R)-Delta(8')-4'-hydroxy-5,5',3'-trimethoxy-3,4-methylenedioxy-2',3',4',5'-tetrahydro-2'-oxo-7.3',8.5'-neolignan], isolated from the ethanol extract of leaves of Pleurothyrium cinereum (Lauraceae), has previously been established by NMR and HRMS spectroscopy, and its absolute configuration established by circular dichroism measurements. For the first time, its crystal strucure has now been established by single-crystal X-ray analysis, as the monohydrate, C22H26O7 center dot H2O. The bicyclooctane moiety comprises fused cyclopentane and cyclohexenone rings which are almost coplanar. An intermolecular O-H center dot center dot center dot O hydrogen bond links the 4'-OH and 5'-OCH3 groups along the c axis.}, language = {en} } @article{CoyJovanovicSefkow2010, author = {Coy, Ericsson D. and Jovanovic, Ljubisa and Sefkow, Michael}, title = {One-pot, Pd-catalyzed synthesis of trans-dihydrobenzofurans from o-aminophenols}, issn = {1523-7060}, doi = {10.1021/Ol100433z}, year = {2010}, abstract = {An efficient and facile synthesis of trans-dihydrobenzofurans has been accomplished from o-aminophenols and phenylpropenes via a novel (one-pot) diastereoselective Pd-catalyzed oxyarylation reaction. The development and optimization of this method is described.}, language = {en} } @article{CoyBarreraCucaSussrezSefkow2009, author = {Coy-Barrera, Ericsson David and Cuca-Sußrez, Luis Enrique and Sefkow, Michael}, title = {PAF-antagonistic bicyclo[3.2.1]octanoid neolignans from leaves of Ocotea macrophylla Kunth (Lauraceae)}, issn = {0031-9422}, doi = {10.1016/j.phytochem.2009.07.010}, year = {2009}, abstract = {Di-nor-benzofuran neolignan aldehydes, Delta(7)-3,4-methylenedioxy-3'-methoxy-8',9'-dinor- 4',7-epoxy-8,3'-neolignan-7'-aldehyde (ocophyllal A) 1, Delta(7)-3,4,5,3'-tetramethoxy- 8',9'-dinor-4',7-epoxy-8,3'-neolignan-7'-aldehyde (ocophyllal B) 2, and macrophyllin-type bicyclo[3.2.1]octanoid neolignans (7R, 8R, 3'S, 4'S, 5'R)-Delta(8)'-4'-hydroxy-5'- methoxy-3,4-methylenedioxy-2',3'.4',5'-tetrahydro-2'-oxo-7.3',8.5'-neolignan (ocophyllol A) 3, (7R, 8R, 3'S, 4'S, 5'R)-Delta 8'-4'-hydroxy-3,4,5'-trimethoxy- 2',3',4',5'-tetrahydro-2'-oxo-7.3',8.5'-neolignan (ocophyllol B) 4, (7R, 8R, 3'S, 4'S, 5'R)-Delta(8)'-4'-hydroxy-3,4,5,5'-tetramethoxy- 2',3',4',5'-tetrahydro-2'-oxo-7.3',8.5'-neolignan (ocophyllol C) 5, as well as 2'-epi-guianin 6 and (+)-licarin B 7, were isolated and characterized from leaves of Ocotea macrophylla (Lauraceae). The structures and configuration of these compounds were determined by extensive spectroscopic analyses. Inhibition of platelet activating factor (PAF)-induced aggregation of rabbit platelets were tested with neolignans 1-7. Although compound 6 was the most potent PAF-antagonist, compounds 3-5 showed some activity.}, language = {en} } @article{CoyBarreraCucaSussrezSefkow2009, author = {Coy-Barrera, Ericsson David and Cuca-Sußrez, Luis Enrique and Sefkow, Michael}, title = {Macrophyllin-type bicyclo[3.2.1]octanoid neolignans from the leaves of Pleurothyrium cinereum}, issn = {0163-3864}, doi = {10.1021/Np9000569}, year = {2009}, abstract = {Four new macrophyllin-type bicyclo[3.2.1]octanoid neolignans, (7S,8R,3'S,5'R)-Delta(8')- 5,5',3'-trimethoxy-3,4-methylenedioxy-2',3',4',5'-tetrahydro-2',4'-dioxo- 7.3',8.5'-neolignan (cinerin A), 1, (7R,8R,3'S,4'R,5'R)-Delta(8')-4'-hydroxy- 5,5'-dimethoxy-3,4-methylenedioxy-2',3',4',5'-tetrahydro-2'-oxo- 7.3',8.5'-neolignan (cinerin B), 2, (7S,8R,3'R,4'S,5'R)-Delta(8')-4'-hydroxy- 5,5',3'-trimethoxy-3,4-methylenedioxy-2',3',4',5'-tetrahydro-2'-oxo- 7.3',8.5'-neolignan (cinerin C), 3, and (7S,8R,2'RYS,5'R)-Delta(8')-2'-hydroxy- 5,5'-dimethoxy-3,4-methylenedioxy-2',3',4',5'-tetrahydro-4'-oxo- 7.3',8.5'-neolignan (cinerin D). 4, along with the known diterpene kaurenoic acid 5, were isolated from the leaves of Pleurothyrium cinercum. The structures and configuration of these compounds were determined by extensive spectroscopic analysis. Cinerins A-D (1-4) were tested for their inhibition efficacy of platelet activating factor (PAF)- induced aggregation of rabbit platelets. Compound 3 was the most potent PAF antagonist. Compounds 1-5 were tested against Mycobacterium tuberculosis (H(37)Rv strain) using the MABA method. Compound 5 induced 91.3\% growth inhibition at 50 mu g mL(-1). Compounds 1-5 showed no significant inhibitory activity against some Gram-positive and Gram-negative bacteria by the agar-well diffusion method.}, language = {en} } @article{CoyBarreraCucaSussrezSefkow2009, author = {Coy-Barrera, Ericsson David and Cuca-Sußrez, Luis Enrique and Sefkow, Michael}, title = {COX, LOX and platelet aggregation inhibitory properties of Lauraceae neolignans}, issn = {0960-894X}, doi = {10.1016/j.bmcl.2009.10.069}, year = {2009}, abstract = {The anti-inflammatory potential of 26 neolignans (14 of the bicyclooctane-type and 12 of the benzofuran-type), isolated from three Lauraceae species (Pleurothyrium cinereum, Ocotea macrophylla and Nectandra amazonum), was evaluated in vitro through inhibition of COX-1, COX-2, 5-LOX and agonist-induced aggregation of rabbit platelets. Benzofuran neolignans were found to be selective COX-2 inhibitors, whereas bicyclooctane neolignans inhibit selectively the PAF- action as well as COX-1 and 5-LOX. The neolignan 9-nor-7,8-dehydro-isolicarin B 15 and cinerin C 7 were found to be the most potent COX-2 inhibitor and PAF-antagonist, respectively. Nectamazin C 10 exhibited dual 5-LOX/COX-2 inhibition.}, language = {en} } @article{CoyBarreraCucaSussrezSefkow2009, author = {Coy-Barrera, Ericsson David and Cuca-Sußrez, Luis Enrique and Sefkow, Michael}, title = {PAF-antagonist 7.3 '.8.5 '-connected bicyclo[3.2.1]octane neolignans obtained from three colombian Lauraceae species and their synthesis}, issn = {0032-0943}, year = {2009}, language = {en} } @article{KamlageSefkowPeter1999, author = {Kamlage, Stefan and Sefkow, Michael and Peter, Martin G.}, title = {Cross coupling of benzylic bromides and vinyl stannanes}, year = {1999}, language = {en} } @phdthesis{Sefkow2001, author = {Sefkow, Michael}, title = {Funktionelle Aromaten : neue Konzepte zur stereoselektiven Synthese phenolischer Naturstoffe und zur Derivatisierung aromatischer Verbindungen}, pages = {171 S.}, year = {2001}, language = {de} } @article{KamlageSefkowPeter2001, author = {Kamlage, Stefan and Sefkow, Michael and Peter, Martin G.}, title = {A short synthesis of biologically active lignan analogues}, year = {2001}, abstract = {beta-Benzyl-gamma-butyrolactones were synthesized in four transition metal catalysed reactions from butynediol, and alkylated to afford new, biologically active lignan analogues.}, language = {en} }