Diastereoselectivity Switch in the Pd(0)/InI-Mediated Reactions of β‑Lactams with Aldehydes: An Entry into Nonracemic Semiprotected (3E)‑2,6-Enediols
journal contributionposted on 18.09.2019 by Sylwia Domin, Paulina Plata, Bartosz K. Zambroń
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The switch from N-methylimidazole (N-MI) to the Et3N N-ligand efficiently alters diastereoselectivity in Pd(0)/InI-mediated allylations of aldehydes with β-lactam-derived organoindiums. As a result, (3E)-selective allylations and crotylations of a variety of aliphatic and (hetero)aromatic aldehydes with differently substituted chiral ε-amido-allylindiums were developed. Depending on the relative β-lactam configuration, the reactions occur under kinetic or thermodynamic control, with effective remote 1,5- or 1,4,5-asymmetric induction to afford a diversity of previously unavailable (3E)-2,5-syn-2,6-anti-, (3E)-2,5-anti-2,6-anti-, and (3E)-2,5-anti-2,6-syn-substituted enediols, amino alcohols, and homoallylic alcohols in modest to high yields and with moderate to excellent diastereoselectivity. The effect of the N-ligand as well as β-lactam and aldehyde structures on the yield and stereoselectivity was investigated.