J . Am. Chem. Soc. 1994,116. 3645-3646
A Tandem Cycloaddition Protocol for the Controlled Synthesis of [nlhdderanes: New Rods and Spacers
3645
alicyclic framework sets them aside from the curved binanes and [nlpolynorbornanes. This is apparent in Figure I , which shows minimum energy configurations" for the three protype molracs: [IOIladderane (1). the 100 binane 2s. and [5]polynorbornane (3). Thecurved natureof binane spacers is well illustrated in the
Ronald N. Warrener' and Giovanni Abbenante Cenfre for Molecular Architecfure University of Central Queensland Rockhampton. Queensland, 4702 Australia
pr
I I I I1I I I
I1
[lolladderane 1
" 10- binane
Colin H. L. Kennard
l a R=H: Zb R=C02Ma
Small Molecule X- Ray Diffraction Loborafory Uniuersify of Queensland St. Lucia, Queensland. 4067 Austrolia
R
R
Received May I I , 1993
As thecomplexity and specificityof supramolecular structures continue to grow, so the need for new structural elements in molecular design becomes more acute. In the arena of spacer molecules. therearenow a numberofalternative typesavailable.l.2 including the binane class which we described some years ago." Theseand related polyalicyclicsystems form rigid molecular racks (molracs)' which have proved to be versatile spacer molecules, finding wide application in the study of energy transfe? and also as templates for the control of polymerization.' As a further extension of the molrac mncept. we now report on the synthesis of a new range of rigid rods based on the [n]ladderanes.6 The individual topology of exo,exo-fused [nlladderanes is revealed by molecular modeling, where the straightness of their Author to whom correspondence should be addrased. ( I ) Staffma and rodana: (a) Kaszynski. P.: McMurdic. N. D.: Miehl. J. J. Am. Chsm. Sw.1992.114.601420. (h) Zimmcrman. H.E.:King. R. K.: Meinhardt. M. B. J . Org. Chem. 1992.57. 5484-5492. (e) Butterfield. K.; Thomas. E.J. Synlerr 1993.41 1 4 1 2 . Aromatin and hcteroaromatia: (d) C o n i . F.: Cinquini. M.: Annuriala. R.: Siegd. J. S. J. Am. Chrm. Sw. 1993. 115. 5330-5331. (e) Retek. J.; Manhall. L.;Wolak, R.;Parris, K.; Kiltoran. M.;Arkew. B.;Ncmcth. D.; 1slam.N. J . Am. Chem.Soe. 1985,107. 7476-7481. Porphyrins: (0 Giraudcau. A,: Gisselhrecht. I. P.: Grorr. M.: Wciss. J. 1. Chem. Soe., Chcm. Commun. 1993. 1103-1105. (2) Molraa: (a) Wancncr. R. N.; Pill, 1. G.: Butler, D. N. J. Chcm.Sw.. Chcm. Cammun. 1983. 134LL1342; (h) Warrcncr. R. N.; Groundwater, P.: Pill. 1. G.: Butler. D. N.: Russell. R. A. Tetrahedron Lett. 1991. 32, 18851888.
(3) Wancner. R. N. Chrm. AUII. 1992.59. 578-581. (4) (a) Paddon-Row, M. N.; Vcrhocvcn. J. W. New J. Chem. 1991. IS. 107-1 16. (h) Gollra. A.: Kcyic.P. J.; PaddomRow. M. N. Terrohedron 1992. 48.1663-7678. ( 5 ) Fcldman. K. S.: b b a . 1. S.: Tcwalt. G. L. J . Org. Chem. 1992, 57. d
