Asymmetric Organocatalysis of Activated Alkynes and Enynes

Abstract

Enantioselective organocatalytic protocols for the functionalization of electron-deficient internal alkynes and enynes are reviewed. This review focuses on the applicability of activated conjugated π-systems in asymmetric synthesis for providing diversified chiral entities under metal-free reaction conditions. Various organocatalytic strategies with different catalytic modes are demonstrated.

Asymmetric Organocatalytic Reactions of Activated Racemic Allenes

“…The reports that rely on in situ generations of racemic allenes from activated alkynes, followed by enantio-functionalization are exempted in this review. [24]…”

“…The literature is classified according to the nature of substrates, mode of activation, and the type of reaction. The reports that rely on in situ generations of racemic allenes from activated alkynes, followed by enantio‐functionalization are exempted in this review [24] …”

Sequential organo and metal catalyzed reaction between 3-pyrrolyloxindoles and linear nitroenynes: access to cyclic aza-spirooxindoles

“…Electron-poor 1,3-enynes have been found to be an important synthon for the preparation of densely functionalized skeletons. 11 Among them, 1,3-enynes with a strong electron-poor nitro group at the C1 (linear) position represent a valuable Michael acceptor, due to the presence of a triple bond in the corresponding Michael adducts. In the organocatalytic 1,4-addition of nitroenynes, a number of carbonyl compounds have been utilized as nucleophiles and a variety of heterocyclic compounds were obtained.…”