Hexafluoroisopropanol-Mediated Cascade Cyclization for Construction of α‑Amino-γ-spirolactones
Haoran Li1, Fangting Huang1, Claire Miesch2
1Key Laboratory of Molecular Target & Clinical Pharmacology and the State Key Laboratory of Respiratory Disease, School of Pharmaceutical Sciences, Guangzhou Medical University, Guangzhou, Guangdong 511436, China.
Abstract:
Given the ubiquity of spirolactones in pharmaceutical agents, natural products, and small-molecule chemical probes, considerable research has been devoted to streamlining their synthesis. Yet, the preparation of α-amino-γ-spirolactones, which combine two key motifs in drug discoveryspirocycle and amine unitsremains underdeveloped. Here, we demonstrate that readily accessible building blocksamines, glyoxylic acid, and unactivated alkenescan be rapidly converted to complex three-dimensional α-amino-γ-spirolactones and related compounds employing a hexafluoroisopropanol-promoted cascade cyclization. This protocol is general, efficient, scalable, and applicable to the mid- and late-stage functionalization of medicinally relevant molecules, while displaying excellent sustainability metrics. All those features, along with preliminary results indicating the potential bioactivity of spirolactones against cancer cells, make the reported methodology a promising tool for drug discovery.
Related Concept Videos
Acid-Catalyzed α-Halogenation of Aldehydes and Ketones
In the first step of the mechanism, the acid protonates the carbonyl oxygen resulting in a resonance-stabilized cation, which subsequently loses an α-hydrogen to form an enol tautomer. The C=C bond in an enol is highly nucleophilic because of the electron-donating nature of the –OH group. Consequently, the double bond attacks an electrophilic halogen to form a...
Base-Promoted α-Halogenation of Aldehydes and Ketones
Crossed Aldol Reaction Using Strong Bases: Directed Aldol Reaction
Formation of Halohydrin from Alkenes
Preparation of Epoxides
Epoxides result from alkene oxidation, which can be achieved by a) air, b) peroxy acids, c) hypochlorous acids, and d) halohydrin cyclization.
Epoxidation with Peroxy Acids
Epoxidation of alkenes via oxidation with peroxy acids involves the conversion of a carbon–carbon double bond to an epoxide using the oxidizing agent meta-chloroperoxybenzoic acid, commonly known as MCPBA. Since the O–O bond of peroxy acids is very weak, the addition of electrophilic oxygen of peroxy acids to...
α-Alkylation of Ketones via Enolate Ions


![Solid-phase Synthesis of [4.4] Spirocyclic Oximes](/_next/image?url=https%3A%2F%2Fcloudfront.jove.com%2FCDNSource%2Fteasers%2F58508.jpg&w=3840&q=50)