Abstract
Cp2 TiCl2 is an efficient catalyst for the diastereoselective mono-oxidation of 2-substituted 1,3-dithianes and 1,3-dithiolanes by tert -butyl hydroperoxide; comparable stereoselectivities and better yields than Ti(i -PrO)4 were obtained. Activities are similar, provided activated 4Å molecular sieves are present in the titanocene-promoted process. Furthermore, Cp2 TiCl2 is a more moisture stable compound than Ti(i -PrO)4 and therefore can be used in catalytic amounts of 1 mol%.
Key words
diastereoselectivity - oxidations - metallocenes - sulfoxides - titanium
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