Allylzinc bromide homoallyl amines

One of the first reports dealing with the carbozincation of alkenes by allylic organozinc reagents was the addition of allylzinc bromide to the homoallylic amine 118 which occurred in refluxing THF. A secondary organozinc 119 was regioselectively produced and provided the amine 120 after hydrolysis. A small amount of aminoalcohol 121, resulting from oxidation of 119, was also isolated when the reaction mixture was exposed to air (equation 52)80,81. 

Failure for Grignard reagents to undergo similar additions to homoallylic amines may be explained by the greater stability of the complexes between an amine and zinc rather than magnesium. By contrast, addition of allylzinc bromide to allyl or homoallyl alcohols proceeded considerably less efficiently compared to amines and the regioselectivity was reversed (equation 55)81. 

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