NHC-Ni catalyzed enantioselective synthesis of 1,4-dienes by cross-hydroalkenylation of cyclic 1,3-dienes and heterosubstituted terminal olefins.

Chen, Yang; Dang, Liang; Ho, Chun-Yu · Nat Commun · 2020

basic_science · Level V

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Abstract

Enantioenriched 1,4-dienes are versatile building blocks in asymmetric synthesis, therefore their efficient synthesis directly from chemical feedstock is highly sought after. Here, we show an enantioselective cross-hydroalkenylation of cyclic 1,3-diene and hetero-substituted terminal olefin by using a chiral [NHC-Ni(allyl)]BAr<sup>F</sup> catalyst. Using a structurally flexible chiral C<sub>2</sub> NHC-Ni design is key to access a broad scope of chiral 1,4-diene 3 or 3' with high enantioselectivity. This study also offers insights on how to regulate chiral C<sub>2</sub> NHC-Ni(II) 1,3-allylic shift on cyclic diene 1 and to build sterically more hindered endocyclic chiral allylic structures on demand.