114925-63-2Relevant academic research and scientific papers
syn-(1,3)Cyclophanes by Twofold Photocyclodimerization
Meier, Herbert,Prass, Ellen,Noller, Klaus
, p. 1637 - 1642 (2007/10/02)
Thy syn-(1,3)cyclophane 4 is obtained by a twofold dimerization of the 1,3-disubstituted benzene derivative 3 during photolysis in solution.A combined irradiation of 5 in solid state/solution yields the analogous system 6 with ester groups.Both reactions are strictly regiospecific by head-to-head linkage and stereospecific concerning the syn geometry in the cyclophane and the trans configuration of the substituents on the four-membered rings.The only stereochemical freedom consists in the arrangement of the four-membered rings, which corresponds in 4/6a, b, c to the possible rotamers in 3 and 5.Whereas the skeleton in 4 is rigid, 6 shows a slow inversion of the central ten-membered ring at room temp.The elucidation of the stereoisomers is performed by NOE measurements.
