Unprecedented Noncatalyzed anti-Carbozincation of Diethyl Acetylenedicarboxylate through Alkylzinc Group Radical Transfer

The radical carbozincation of diethyl acetylenedicarboxylate, performed at room temperature in the presence of air, leads to fumaric derivatives through a selective alkylzinc group radical transfer controlled by coordination. The total trans stereocontrol is unprecedented, carbocupration is well-known to give the reversal selectivity at low temperature, while classical radical addition methodologies lead to mixtures of isomers.