Complex Hydroindoles by an Intramolecular Nitrile-Intercepted Allylic Alkylation Cascade Reaction

Modular Synthesis of Polar Spirocyclic Scaffolds Enabled by Radical Chemistry

Herein, we report a highly modular strategy to access spirocyclic scaffolds from abundant starting materials, i.e., cyclic ketones and α-amino or oxamic acids. The sequence proceeds through a straightforward Knoevenagel condensation, followed by a domino Giese-type reaction/base-mediated cyclization process, to deliver a broad scope of polar spirocyclic scaffolds in good to excellent yields. The products can be readily diversified, thus increasing the versatility of our method to gain rapid access to libraries of potential druglike molecules.

Recent advances in the synthesis of cyclic compounds using α,α-dicyanoolefins as versatile vinylogous nucleophiles

This article provides a review of the applications of α,α-dicyanoolefins as versatile vinylogous nucleophiles in the synthesis of various cyclic compounds, covering the literature from the past 13 years.

Phosphine-Catalyzed (3 + 2)/(3 + 2) Sequential Annulation of γ-Vinyl Allenoates: Access to Fused Carbocycles

The first (3 + 2)/(3 + 2) sequential annulation of γ-vinyl allenoates with alkylidenemalononitriles enabled by phosphine catalysis has been reported. A broad range of structurally dense tetra- and penta-substituted bicyclic[3,3,0]octene derivatives, containing a quaternary center and three sequential stereogenic center, were synthesized in good to excellent yields. In this approach, three new C-C bonds are formed in one pot, and εC and αC of γ-vinyl allenoate are two electrophilic centers, whereas its γC exhibits nucleophilic reactivity.

Stereoselective Synthesis of Fused Vinylcyclopropanes by Intramolecular Tsuji-Trost Cascade Cyclization

A stereoselective intramolecular Tsuji–Trost cascade cyclization of (homo)allylic vicinal diacetates with a pendant β-ketoamide or related carbon nucleophile to give γ-lactam-fused vinylcyclopropanes is reported. In addition to two new rings, the products contain three new C–C stereocenters (two of which are quaternary) with a 9:1 dr. Moreover, the reaction proceeds in >94% enantiospecificity with optically enriched starting materials, using an inexpensive carbohydrate as the source of chirality.

Tetrahydrobenzochromene Synthesis Enabled by a Deconjugative Alkylation/Tsuji-Saegusa-Ito Oxidation on Knoevenagel Adducts

A modular and practical route to versatile cyano-1,3-dienes by a sequence involving deconjugative alkylation and "Tsuji-Saegusa-Ito oxidation" is reported. In this letter, the versatility of the products is also explored, including a route to benzochromene scaffolds common to many natural products.