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In comparative studies, we have been able to demonstrate that redox catalysts based on transition-metal complexes using l,lO-phenanthroline-5,6-dione as a ligand or based on N-methylated l,lO-phenathroline-5,6-dione acting via hydride ion abstraction are superior to alternative methods for the redox catalytic aerobic or indirect electrochemical in situ NAD(P)+ regeneration in enzymatic syntheses using alcohol dehydrogenases as production enzymes. Under preparative conditions in the gram scale we were able to obtain turnover frequencies of up to 130 turnovers per hour with respect to the redox catalyst. These are far larger than those of the presently most popular regeneration system.

A new organometallic approach to novel, functionalised, helicene-like quinones and bisquinones has been developed based on the chromium-templated [3+2+1] benzannulation reaction. The [5]helicene-analogous monocarbene chromium complexes 4, 5, 17 and 19, derived from dibromo-substituted methylene-or silylene-tethered binaphthols 2 and 3, react with various alkynes to give [6]helicene-like quinones 6-13 and 20-29 after oxidative work-up. A rare competition of angular vs. linear annulation is observed for the incorporation of phenylacetylene that affords quinones 21/22 and 28/ 29. Protection of the phenolic benzannulation product with camphanic acid chloride 14, followed by chromatographic separation, provides access to enantiopure [6]helicene-like

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