The cycloaddition of acetylenes with azides to give the corresponding 1,4-disubstituted 1,2,3-triazoles is reported using immobilised reagents and scavengers in pre-packed glass tubes in a modular flow reactor.

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N-Salicylideneanilines are interesting model compounds for understanding solid-state photochromism. The introduction of bulky substituents (trityl or tert-butyl groups) by chemical modification of the N-salicylideneaniline derivative is an effective method to build up photochromic solids. Alternatively, we propose, herein, a supramolecular approach to design photochromic materials which involves the introduction of a bulky anion in the structure. In this context, this is the first report on N-salicylideneamino-1-alkylpyridinium salts (iodide and tetraphenylboride salts). Iodide salts were obtained by alkylation of the parent N-salicylideneaminopyridine with the appropriate iodoalkane (iodomethane or iodoethane) in acetone. The iodide salts were used as the starting material for the production of tetraphenylborate salts by anion-exchange in methanol. All solids were characterized by means of X-ray diffraction and absorption spectroscopy. The effect of different counterions as well as the effect of the crystal structure on the solid-state photochromism is investigated.

No abstract

The regioselectivity of the Chx2BCl/Et3N‐mediated (Chx = cyclohexyl) aldol reactions of ketones of general structure 2 has been studied and was shown to depend on both ketone structure and solvent. Useful levels of regioselectivity in favour of any of the two possible regioisomers were obtained in either pentane or diethyl ether. The relative configuration of the aldol products was assigned by 1H NMR studies of six‐membered‐ring derivatives. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)