The reaction of unhindered olefins with sodium hydrogen telluride in refluxing ethanol produces dialkyltellurides by anaddition process which shows prominent Markownikov selectivity.
Owing to its utility in organic synthesis, the action of sodium hydrogen telluridel, NaTeH, on a variety of functional groups2a'j has attracted considerable interest in the last few years.
Carbon-carbon double bonds, when conjugated with carbonyl groups3arbor with aromatic ringsI, are reduoed by NaTeH, but isolated double bonds are stated not to react.
Here we wish to report that NaTeH does, in fact, reactamoothlywith unhindered olefins to afford products containing well defined carbontellurium bonds. These products are dialkyltellurides,sometimes accompanied by the corresponding ditellurides.
For example, when monosubstituted olefins 1 and 2 were reacted with excess NaTeH in ethanol under reflux for 24 h., mixtures of tellurium containingderivatives 1,9 and 2,R were respectively obtained in 92% and 96% yields after usual work up5.
A.3 shown by 1R NMR analysis, the relative ratio of products derived from undecylenic acid 1 wa.9 lO,lO-telluride a6 79%, lO,lO-ditelluride ah6 13% and ll,ll-ditelluride ~6 9%. The main product Sn was identical with that obtained by reacting lo-bromo-undecanoic acid 57 with one equivalent of NaTeH in ethanol at room temperature. Furthermore, treatment of the mixture of products 3 and P with nickel boride*j at room temperature afforded undecanoic acid 4 in 90% global yield from 1.
In the same way, 6-phenoxy-1-hexene pea was found to give 85% of secondary telluride 2, 9% of primary telluride Bn and 5% of primary ditelluride fig. Complete detelluration was also achieved by means of nickel boride to obtain I-phenoxyhexane 9 in 92% global yield from 2.