Twenty years ago, we described the two first preparative Mn-catalyzed organometallic reactions2, the stereospecific coupling of alkenyl iodides providing symmetrical 1,3-dienes3 and the reduction of aryl or alkenyl halides.4 The reduction reaction must be performed with secondary or tertiary alkyl Grignards to obtain only the reduction product. Indeed, with primary alkyl Grignards a variable amount of cross-coupling product is formed concurrently with ...
