Figure 7. Chromatographic resolution of racemic BINOL on (+)-PTrMA. Column, 25 cm × 0.46 cm (i.d.). Eluent, methanol. Flow rate, 0.5 mL/min. Reprinted with permission from ref 46.

No abstract

As long as 50 years ago theoretical calculations predicted that Möbius annulenes with only one π surface and one edge would exhibit peculiar electronic properties and violate the Hückel rules. Numerous synthetic attempts notwithstanding, the first singly twisted Möbius annulene was not prepared until 2003. Here we present a general, rational strategy to synthesize triply or even more highly twisted cyclic π systems. We apply this strategy to the preparation of a triply twisted [24]dehydroannulene, the structure of which was confirmed by X-ray analysis. Our strategy is based on the topological transformation of 'twist' into 'writhe'. The advantage is twofold: the product exhibits a lower degree of strain and precursors can be designed that inherently include the writhe, which, after cyclization, ends up in the Möbius product. With our strategy, triply twisted systems are easier to prepare than their singly twisted counterparts.

No abstract

New diazocines as photochromic switches for the surface functionalization via the "platform approach" were synthesized and characterized. Symmetric diazocines as well as asymmetric molecules based on an indane scaffold were ob-