Selectivity on the reaction of vinylic tellurides with butyllithium in thepresence of carbonyl compounds.

The treatment of isomeric vinylic tellurides 5-7 with butyllithium in THF a t -78 degrees C in the presence of a carbonyl compound such as benzaldehyde or cyclohexanone was studied. High selectivity of the attack at the tellur ium atom was observed. In most cases, the corresponding allylic alcohol was obtained as the only (or major) product instead of the alcohols derived by the 1,2 addition of BuLi at the carbonyl compound. Similar results were ob tained using the ketenetelluroacetal 14 instead of the vinylic monotellurid es. (C) 1999 Elsevier Science Ltd. All rights reserved.