Organocopper compounds Lewis acid-activation

Whereas these and other reports did not indicate the possibility of 1,4-cuprate additions to activated dienes, Yamamoto and co workers" showed in their seminal contributions that this is indeed feasible while the reaction of methyl sorbate with the Gilman cuprate M-Bu2CuLi provided exclusively the 1,6-addition product, the reagent formed from butylcopper and the Lewis acid boron trifluoride led to the 1.4-adduct as the major product (equation 15). The synthetically veiy useful organocopper compounds RCu have been named Yamamoto reagents. In certain cases, the regioselectiv-... 

---