Carbon-carbon bond formation reactions employing addition of radical 1 to alkenes 2 have been successfully applied in organic synthesis. l Alkylmercury hydrides and tri-n-butyltin hydride act as efficient traps which convert adduct radicals 3 to products 4 before polymerization can occur (Scheme I).* In the case of the tin method, radicals 5 propagate the chain by reaction with suitable educts 6 to form radicals 1. Halides, xanthanes, selenides, ...