Highly Regio- and Enantioselective Dienylation of p‑Quinone Methides Enabled by an Organocatalyzed Isomerization/Addition Cascade of Allenoates
journal contributionposted on 17.05.2019, 15:50 by De Wang, Ze-Feng Song, Wei-Jia Wang, Tao Xu
A novel catalytic asymmetric dienylation of para-quinone methides with allenoates has been developed. Under mild conditions catalyzed by (R)-SITCP, various dienylated bisarylmethides were obtained in moderate to good yields (up to 82% yield) and excellent enantioselectivities (90–98% ees). The efficacy and robustness were demonstrated by 27 examples of chiral dienylation products. A plausible mechanism, which involved 1,2 H-shift and umpolung of allenoates, was proposed based on deuterium labeling experiments and previous reports.