An Enantioselective Synthesis of (R)‐5,6‐Octadecadienoic Acid

A convenient, scalable, and highly enantioselective total synthesis of (R)‐5,6‐octadecadienoic acid was developed by using the recently established ATA (allenylation of terminal alkynes) reaction of TBS‐protected (TBS = tert‐butyldimethylsilyl) propargyl alcohol with n‐dodecanal in the presence of (R)‐α,α‐diphenylprolinol as the chiral source. The axial chirality of the allene unit withstood the many common organic transformations that were needed to achieve the total synthesis with a high ee (enantiomeric excess) value.