Reactions of N-protected amino acid chlorides with carbonyl compounds in the presence of SmI2 were investigated. Decarbonylation followed by a cross coupling between amino moiety and aldehyde or ketone is observed. By the use of FMOC derivatives, N-protected amino alcohols were isolated in moderate yields.
We have investigated the reactivity of SmI2 towards acid chlorides : coupling reactions and condensation reactions of acid chlorides with aldehydes or ketones led to a-ketolsI2.
We have recently extended this reaction to SmCp2, which displays the same reactivity. Interestingly the cyclopentadienyl ligand stabilizes the intermediate species and it has been established that acyl samarium compounds are involved in these reactions3. The reactivity of functionalized acid chlorides has also been examined. For ortho allyloxybenzoic acid chlorides, a double cyclization reaction takes place4. A different pathway is observed when a-alkoxyacid chlorides are reacted with aldehydes or ketones and SmI2 to give 1,2-glycol monoethers 5. In this reaction, decarbonylation of the acid chloride by SmI2 occurs first, probably via an acyl radical intermediate. The a-oxygen atom is thought to play an important role in the decarbonylation probably through radical stabilization.