Chiral 2‐Amino‐1, 3‐butadienes: New Reagents for Asymmetric Cycloadditions

You can teach an old dog a new trick! In recent studies of the thoroughly examined Diels–Alder reaction, the research groups led by Enders and Barluenga employed chiral 2-aminobutadienes of type 1(R is for example H, CH2OH) to achieve total regio- and diastereoselectivities, and enantioselectivities of up to 99% ee. This type of chiral diene has the advantage that it can be prepared from commercially available starting materials, its chiral component can, in principle, be recovered, and even compounds with seven-membered rings are accessible in a one-pot reaction.