Hydrosilylation and Hydrophosphonylation

Recent advances in the asymmetric hydrosilylation of ketones and imines have been reviewed.276 

Hydrosilylation of ketones, and also of a- and /i-kclo esters and amides, has been achieved using polymethylhydrosiloxane in methanol, with various zinc(II) catalysts.277 The reactions are faster than in aprotic solvents, and show some enantios-electivity with chiral diaminozincs. 

A salalen ligand (a hybrid salicylideneimine-salicylamine) has been coordinated to aluminium to serve as an enantioselective catalyst for aldehyde hydrophosphonylation of aldehydes.278 

Catalytic enantioselective a-aminations and a-oxygenations of carbonyl compounds have been reviewed.279 

The formaldehyde-sulfite reaction displays non-linear dynamics it is a clock reaction with a sudden pH excursion (from ca 7 up to ll).280 The induction period in batch processes is explained by the internal buffer systems, HS03 -S03. However, flow reactors also exhibit pH oscillations and bistability. 

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