124755-93-7Relevant academic research and scientific papers
(Z)-2,2'-Disubstituted Bifluorenylidenes by Intramolecular Desulfurdimerization Reactions
Yip, Yu Chi,Wang, Xiao-jun,Ng, Dennis K. P.,Mak, Thomas C. W.,Chiang, Ping,Luh, Tien-Yau
, p. 1881 - 1889 (2007/10/02)
W(CO)6-mediated intramolecular desulfurdimerization reactions have been used in the syntheses of bridged 2,2'-disubstituted bifluorenylidenes in satisfactory yields.Ring sizes from 12 to 24 can be synthesized by this reaction.The extension of this reaction for the synthesis of bifluorenylidene-hinged crown ethers is described.The X-ray structure of 6i has been determined.The two fluorenylidene moieties are each planar, making a dihedral angle of 44.9 deg.The first optically active bifluorenylidenes were unequivocally synthesized, and the barriers for the racemization of two such molecules have been determined (12 kcal/mol).The racemization process may arise from the pyramidalization at C9 and/or C9' followed by rapid twisting along the C9-C9' bond.
