Copper(I) thiophen-2-carboxylate was successfully employed in the trimerization of [2.2.1] bicyclic vic-bromotrimethyltin olefins (in their racemic composition), bearing different functionalities, to invariably obtain almost quantitative yields of the syn and anti tris-annelated benzenes. The two isomers come in different ratios, smaller than or equal to the statistical 1:3 ratio, depending on the steric hindrance opposed by the functionalities. In the case of enantiopure (3-bromo-4,7,7-trimethylbicyclo[2.2.1]hept-2-en-2-yl)trimethylstannane, the 1:9 ratio found with Cu(NO(3))(2).3H(2)O increases to 1:6.
Download full-text PDF |
Source |
---|---|
http://dx.doi.org/10.1021/jo020396s | DOI Listing |
J Am Chem Soc
December 2006
Laboratory of Biostructural Chemistry, Graduate School of Life Sciences, Tohoku University, Aoba-ku, Sendai 981-8555, Japan.
Total synthesis of structure 1 originally proposed for brevenal, a nontoxic polycyclic ether natural product isolated from the Florida red tide dinoflagellate, Karenia brevis, was accomplished. The key features of the synthesis involved (i) convergent assembly of the pentacyclic polyether skeleton based on our developed Suzuki-Miyaura coupling chemistry and (ii) stereoselective construction of the multi-substituted (E,E)-dienal side chain by using copper(I) thiophen-2-carboxylate (CuTC)-promoted modified Stille coupling. The disparity of NMR spectra between the synthetic material and the natural product required a revision of the proposed structure.
View Article and Find Full Text PDFJ Org Chem
November 2002
Dipartimento di Scienze Ambientali and Dipartimento di Chimica, Università Ca' Foscari di Venezia, Dorsoduro 2137, Italy.
Copper(I) thiophen-2-carboxylate was successfully employed in the trimerization of [2.2.1] bicyclic vic-bromotrimethyltin olefins (in their racemic composition), bearing different functionalities, to invariably obtain almost quantitative yields of the syn and anti tris-annelated benzenes.
View Article and Find Full Text PDFEnter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!