In synthetic organic chemistry, Z-olefins are a challenging synthetic target to produce in the lab due to their relative thermodynamic instability. The Z-olefins form an unsaturated compound with a CnH2n formula that can be readily isomerized. Analogous reactions used to synthesize optically active Z-olefin products are rare. In a new report now published on Science, Ru Jiang and a research team at the University of Chinese Academy of Sciences in Shanghai, China, detailed an iridium-catalyzed asymmetric allylic substitution reaction to retain Z-olefin geometries while establishing an adjacent quaternary stereocenter. The team observed the formation of transient anti-π-allyl-iridium intermediates and their capture by external nucleophiles (electron donor) before isomerization to form thermodynamically more stable syn-π-allyl-iridium counterparts. The results provide a promising method to prepare chiral Z-olefin compounds in the lab.
Click here for original story, Iridium-catalyzed Z-retentive asymmetric allylic substitution reactions
Source: Phys.org