Recent Chemistry of Bullvalene

Abstract

Dedicated to Professor R. Criegee on the occasion of' his 65th birthdayThe essential structural element of bullvalene is the homotropilidene system. Thus in any discussion of the chemistry of' bullvalene, all bridged homotropilidenes must also be considered. The present article deals with new syntheses and with the thermal behavior of the homotropilidene system and of bullvalene. Emphasis is also placed on the syntheses and the NMR-spectroscopic behavior of complexed bullvalene, of monosubstituted, disubstituted, and fused bullvalenes, and of some benzobullvalene derivatives.

2,6‐Barbaralane Dicarbonitrile: A Probe for Dewar‐Hoffmann‐Type Homoaromatic Molecules

“…So far, no such compound is known. We now report a simple synthesis of 2,6-barbaralane dicarbonitrile (6), which should allow an experimental investigation of the above predictions.…”

“…bicyclo[3.3.1]nona-2,6-dieneix' and barbaralane (1b)I9l, respectively. Like barbaralane (lb), (6) exhibits averaged NMR spectra at ambient temperature. In the 50-MHz 13C-NMR spectrum of (6) in [D2]dichloromethane, the signal of C-2/C-6 as well as that of C-4/C-8 begins to broaden only at -60 OC"oi.…”

The technology—science interaction: Walter Reppe and cyclooctatetraene chemistry

“…The original infra-red and Raman spectra favoured the crown form, but the X-ray spectra and electron diffraction data confirmed as early as 1948 that COT normally exists in the strainless tub form. 61 The second advance was the discovery of the role played by the tropylium carbocation in COT chemistry. There are two important advances, nonetheless.…”

Synthesis and Analysis of Substituted Bullvalenes

“…It formed the basis of extensive studies into bullvalene chemistry by Schrçder and co-workers, and the preparation of many substituted examples. [5] Rational synthetic strategies towards bullvalene have also been devised by the research groups of Doering [6] and Serratosa, [7] both employing a transannular cyclopropanation as a key step. Recently, Ferrer and Echavarren introduced a new approach based on the goldcatalysed synthesis of barbaralones.…”