Unusual Ester‐Directed Regiochemical Control in endo‐Selective Asymmetric 1,3‐Dipolar Cycloadditions of Azomethine Ylides with β‐Sulfonyl Acrylates

One of the key features of this ester-controlled endo-selective 1,3-dipolar cycloaddition is that high yields and excellent selectivities are observed for a range of imino esters, especially imino esters derived from α-substituted amino acids.