ALKYLIRON AND ALKYLCOBALT REAGENTS .4. ALDEHYDE-SELECTIVE CYANOALKYLATION WITH CYANOALKYL DERIVATIVES OF IRON(II) AND OTHER TRANSITION-METALS

For the transfer of the cyanomethyl residue with high aldehyde vs. ketone selectivity, the Fe reagent 3a is a good alternative to the known Ti reagent 1 a[2], whereas analogous reagents with the metals Mn, Co, Ni or Cu are unfavorable. For the aldehyde- vs. ketone-selective transfer of the branched residues 1-cyanoethyl and cyanoisopropyl, the Fe reagents 3b and 3c are distinctly better than the Ti reagents 1b and 1c.