A series of 1,8-dichloroanthracene precursor molecules with substituents in C-10 position of different steric demand (cyclohexyl, tert-butyl, methyl, isopropyl, n-butyl, phenyl, benzyl, trimethylsilylethinyl) were synthesised and subjected to electrocyclic cycloadditions with chlorobenzyne generated from 3-chloroanthranilic acid. The aim was to steer the regioselectivity of the addition reaction by the steric repulsion between this C-10 substituent and the chlorine substituent at the benzyne intermediate. With H as C-10 substituent the reaction leads to 23 % syn and 77 % anti form. With the small methyl group a syn/anti ratio of 37:63 was achieved. Contrary to our expectations the large C-10 substituent tert-butyl

Gold nanoparticles on a metal-insulator-metal junction locally enhance the absorption of few-cycle laser pulses. The locally heated electron gas leads to thermionic emission exceeding multiphoton emission and allows detection of single nanoparticles.

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