Unsolvated Grignard reagents with WCl6 are effective cocatalysts in the olefin metathesis. Activity of WCl6-BuMgI in benzene medium is comparable with those derived from BuLi. The optimum ratio of BuMgI to WCl6 was 2.0, and products of Friedel-Crafts reaction were less than 3% when the ratio was more than 1.5. The addition of 1% ethylether to the benzene medium deactivated the catalyst essentially. The mechanism of the deactivation was discussed.
