1,1′-Bi(trishomobarrelenyl) – Synthesis and Chiroptic Properties

✍ Scribed by Armin de Meijere; Karsten Rauch; Bernhard Schrader; Farina Brackmann; Roland Pfoh; Stephan Rühl; Yasunaka Katoh; Yoshio Okamoto; Matthew D. Wodrich; Clémence Corminboeuf; Peter R. Schreiner

• Publisher: John Wiley and Sons
• Year: 2009
• Tongue: English
• Weight: 207 KB
• Volume: 2009
• Category: Article
• ISSN: 1434-193X
• DOI: 10.1002/ejoc.200801111

✦ Synopsis

Abstract

1,1′‐Bi(endo,exo,syn‐pentacyclo[3.3.3.0^2,4^.0^6,8^.0^9,11^]undecyl)[1,1′‐bi(trishomobarrelenyl)] (4) has been prepared as a 1:1 mixture of its meso‐ and d,l‐diastereomers in six steps from trishomobarrelene 1 via the amine 5, the N,N′‐bis(trishomobarrelenyl)sulfamide 6 and the 1,2‐(trishomobarrelenyl)diazene 7 in 16 % overall yield. Crystals of meso‐4 were grown from a pentane solution of the mixture and subjected to an X‐ray structure analysis. The (+)‐ and the (–)‐enantiomer were isolated by HPLC on a chiral‐phase column. They exhibited significantly enhanced molar optical rotations which are consistent with the presence of three helically arranged 1,2‐dicyclopropylethane units in their skeletons. The absolute configuration of the (+)‐enantiomer was assigned on the basis of DFT computed optical rotations of both enantiomers to be all‐(S).(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)