N-Heterocyclic Carbene-Catalyzed Activation of -Chloroaldehydes: Asymmetric Synthesis of 5-Cyano-Substituted Dihydropyranones

: Li S, Chen XY, Liu Q, Peuronen A, Rissanen K, Enders D

Publisher: GEORG THIEME VERLAG KG

: 2017

: Synthesis: stuttgart

: SYNTHESIS-STUTTGART

: 49

: 21

: 4861

: 4868

: 8

: 0039-7881

DOI: https://doi.org/10.1055/s-0036-1588509

An N-heterocyclic carbene (NHC)-catalyzed asymmetric [4+2] annulation of (E)-2-benzoyl-3-phenylacrylonitriles with alpha-chloroaldehydes has been developed. The protocol leads to 5-cyano-substituted dihydropyranones in good to excellent yields with excellent diastereo- and enantioselectivities (up to 93% yield, >20:1 d.r. and 99% ee).