960216-98-2Relevant academic research and scientific papers
Synthesis of novel C2-symmetric 1,3-bis{(1S,2R,3S,4R)-1,7,7-trimethyl-3′H-spiro[bicyclo[2.2.1]heptane-2,2′-furan]-3-yl}benzoimidazolium tetrafluoroborates
Groselj, Uros,Meden, Anton,Stanovnik, Branko,Svete, Jurij
, p. 330 - 342 (2008/09/19)
Two new C2-symmetric benzoimidazolium tetrafluoroborates 19 and 20 were prepared from (1S)-(+)-camphorquinone 1 in seven and eight steps, respectively. Thus, N1-((1S,2R,3S,4R)-1,7,7-trimethyl-4′-methylenedihydro-3′H-spiro[bicyclo[2.2.1]heptane-2,2′-furan]-3-yl)benzene-1,2-diamine 11, available in three steps from 1, was first condensed with 1 to afford amino imines 12 and 13/13′. [3 + 2] Cycloaddition of trimethylenemethane (TMM) to 12 or 13/13′ gave cycloadduct 17, which was successfully reduced to diamine 4 using NaCNBH3. Catalytic hydrogenation of methylene groups of 4 gave the methyl analogue 18. Finally, cyclization of diamines 4 and 18 with triethyl orthoformate furnished the desired C2-symmetric benzoimidazolium tetrafluoroborates 19 and 20, respectively. The structures were determined by NMR techniques, NOESY spectroscopy, and X-ray diffraction.
Synthesis of spiro[bicyclo[2.2.1]heptane-2,2′-furan]-3-amines via stereoselective cycloadditions of trimethylenemethane to (1S,3EZ,4R)-3-arylimino-1,7,7-trimethylbicyclo[2.2.1]heptan-2-ones
Groselj, Uros,Meden, Anton,Stanovnik, Branko,Svete, Jurij
, p. 2365 - 2376 (2008/02/12)
Stereoselective [3+2] cycloadditions of trimethylenemethane (TMM) to the exocyclic C{double bond, long}O and C{double bond, long}N double bonds of (1S,3EZ,4R)-3-arylimino-1,7,7-trimethylbicyclo[2.2.1]heptan-2-ones gave the corresponding spiro[bicyclo[2.2.
