DOI: 10.1002/chem.200600111 Syntheses and Properties of Enantiomerically Pure Higher (n  7) [n2]Triangulanedimethanols and s-[n]Helicenes** Armin de Meijere,* [a] AlexanderF. Khlebnikov, [b] Sergei I. Kozhushkov, [a] Dmitrii S. Yufit, [c] Olga V. Chetina, [c] Judith A. K. Howard, [c] Takuya Kurahashi, [a] Kazutoshi Miyazawa, [d] Daniel Frank, [a] Peter R. Schreiner, [e] B. Christopher Rinderspacher, [e] Mari Fujisawa, [f] Chiyo Yamamoto, [f] and Yoshio Okamoto [f] Dedicated to Professor Nikolai S. Zefirov on the occasion of his 70th birthday Abstract: (P)-(+)-Hexaspiro[2.0.0.0. 0.0.2.1.1.1.1.1]pentadecane [(P)-17] as well as (M)-()- and (P)-(+)-octaspiro- [2.0.0.0.0.0.0.0.2.1.1.1.1.1.1.1]nonade- canes [(M)- and (P)-25]—enantiomeri- cally pure unbranched [7]- and [9]trian- gulanes—have been prepared starting from racemic THP-protected (methy- lenecyclopropyl)methanol 6. The rela- tive configurations of all important in- termediates as well as the absolute con- figurations of the key intermediates were established by X-ray crystal struc- ture analyses. This new convergent ap- proach to enantiomerically pure linear [n]triangulanes for n = 7, 9 was also tested in two variants towards [15]tri- angulane. Some of the most prominent and unexpected features of the newly prepared compounds are the remarka- ble modes of self-assembly of the diols (P)-14, (E)-(3S,3’S,4S,4’S,5R,5’R)-21, (P)-(+)-22, and (E)-31 in the solid state through frameworks of intermo- lecular hydrogen bonds leading to, de- pending on the respective structure, nanotube- [(P)-14,(P)-(+)-22, and (E)- 31], honeycomb-like structures [(E)- (3S,3’S,4S,4’S,5R,5’R)-21] or a supramo- lecular double helix [(P)-(+)- and (M)- ()-22]. Liquid crystalline properties of the esters and ethers of the diols (P)-14,(P)-, and (M)-22 have also been tested. Although all of these [n]triangulanes have no chromophore which would lead to significant absorp- tions above 200 nm, they exhibit sur- prisingly high specific rotations even at 589 nm with [a] 20 D =+ + 672.9 (c = 0.814 in CHCl 3 ) for (P)-(+)-17, + 909.9 (c = 0.96 in CHCl 3 ) for (P)-(+)-25, 890.5 (c = 1.01 in CHCl 3 ) for (M)-()-25, and 1302.5 (c = 0.36 in CHCl 3 ) for (M)- ()-39, and the specific rotations in- crease drastically on going to shorter wavelengths. This outstanding rotatory power is in line with their rather rigid helical arrangement of s bonds, and ac- cordingly these helically shaped un- branched [n]triangulanes may be termed “s-[n]helicenes”, as they repre- sent the s-bond analogues of the aro- matic p-[n]helicenes. Density function- al theory (DFT) computations at the B3LYP/6-31+GACHTUNGTRENNUNG(d,p) level of theory for the geometry optimization and time-dependent DFT for determining optical rotations with a triplet-z basis set (B3LYP/TZVP) reproduce the op- tical rotatory dispersions (ORD) very well for the lower members (n = 4, 5) of the s-[n]helicenes. For the higher ones (n = 7, 9, 15) the computed specif- ic rotations turn out increasingly larger than the experimental values. The re- markable increase of the specific rota- tion with an increasing number of three-membered rings is proportional neither to the molecular weight nor to the number of cyclopropane rings in these s-[n]helicenes. Keywords: chirality · helical struc- tures · optical rotations · self-assem- bly · small ring systems [a] Prof. Dr. A. de Meijere, Dr. S. I. Kozhushkov, Dr. T. Kurahashi, D. Frank Institut für Organische und Biomolekulare Chemie der Georg-August-Universität Gçttingen, Tammannstrasse 2 37077 Gçttingen (Germany) Fax: (+ 49)551-399475 E-mail: ameijer1@uni-goettingen.de [b] Prof. Dr. A. F. Khlebnikov St.-Petersburg State University Department of Chemistry, Universitetskii Prosp. 26 Petrodvorets 198504, St.-Petersburg (Russia) [c] Dr. D. S. Yufit, Dr. O. V. Chetina, Prof. Dr. J. A. K. Howard Department of Chemistry, University of Durham Durham, South Rd., DH1 3LE (UK) [d] Dr. K. Miyazawa Chisso Petrochemical Corporation, Goi Research Center 5-1 Goikaigan, Ichihara, Chiba 290-8551 (Japan) [e] Prof. Dr. P. R. Schreiner, Dr. B. C. Rinderspacher Institut für Organische Chemie der Justus-Liebig-Universität Giessen Heinrich-Buff-Ring 58, 35392 Giessen (Germany) [f] M. Fujisawa, Dr. C. Yamamoto, Prof.Dr. Y. Okamoto EcoTopia Science Institute and Department of Applied Chemistry Graduate School of Engineering, Nagoya University Furo-cho, Chikusa-ku, Nagoya 464-8603 (Japan) [**] Preliminary communication: A. de Meijere, A.F. Khlebnikov, S. I. Kozhushkov, K. Miyazawa, D. Frank, P.R. Schreiner, C. Rinderspach- er, D. S. Yufit, J. A. K. Howard, Angew. Chem. 2004, 116, 6715–6719; Angew. Chem. Int. Ed. 2004, 43, 6553–6557. Supporting information for this article is available on the WWW under http://www.chemeurj.org/ or from the author: Syntheses of the diol (1S,3S,4S,5R,6R,7S,8S,9S)-22 and of the liquid crystalline com- pounds 43a–f, 44a–f and 45a–f. Chem. Eur. J. 2006, 12, 5697–5721 # 2006 Wiley-VCH Verlag GmbH&Co. KGaA, Weinheim 5697 FULL PAPER