Chun Cai

One-Pot Synthesis of 3,5-Disubstituted and Polysubstituted Phenols from Acyclic Precursors

A new strategy for the synthesis of 3,5-disubstituted phenols is established through one-pot Robinson annulation of α,β-unsaturated ketones with α-fluoro-β-ketoesters followed by in situ dehydrofluorination and tautomerization. This method has been extended to the synthesis of polysubstituted phenols and applied in the preparation of biologically active compounds.

Fluorous Lewis acids and phase transfer catalysts

The new phase-separation and immobilization technique known as fluorous biphase system (FBS) has become an active topic among researchers in both industry and academia. A series of fluorous biphasic reactions catalyzed by Lewis acid-type metal perfluorooctanesulfonates and metal bis(perfluorooctanesulfonyl)amides are reviewed in this paper. The recent development of fluorous phase transfer catalyst (PTC) is also discussed.

One-pot fluorination followed by Michael addition or Robinson annulation for preparation of α-fluorinated carbonyl compounds

Fluorination followed by the Michael addition or Robinson annulation of 1,3-dicarbonyl compounds is introduced for the synthesis of acyclic and cyclic α-fluoro-β-ketoesters and α-fluoro-1,3-diketones. The decarboxylation step can also be added to the reaction sequence. High efficiency is achieved by the microwave heating and atom economic one-pot synthesis.

Selective approach to thioesters and thioethers via sp3 C–H activation of methylarenes

Novel C–S cross-dehydrogenative coupling (CDC) approaches for the selective synthesis of thioesters and thioethers have been developed via sp3 C–H activation of methylarenes and subsequent functionalization. The reaction of methylarenes with thiols resulted in thioesters in the presence of a FeBr2/TBHP system, while treatment of methylarenes with thiols in the Pd(OAc)2/O2/TBHP system led to the formation of thioethers. Both the green protocols demonstrate good functional group tolerance and satisfactory yields.

Thiourea Based Fluorous Organocatalyst

This review deals with general and significant development of the fluorous organocatalysts based on thiourea. The applications of fluorous technology are briefly discussed. The implementations of thiourea based catalysts in organic synthesis are focused on in the chapter.

Selective formation of C–N and CN bonds via C(sp3)–H activation of isochroman in the presence of DTBP

An approach for the synthesis of isochroman derivatives via direct C(sp3)–H bond and N–H bond coupling is described. The C–N (amine or amide) and CN (imidate) products can be selectively achieved by controlling the amount of oxidants. Moreover, this metal- and base-free protocol is simple, easy-to-handle, and atom-economical which may have potential application in drug synthesis.

A recyclable fluorous hydrazine-1,2-bis(carbothioate) with NCS as efficient catalysts for acetalization of aldehydes

A fluorous hydrazine-carbothioate organocatalyst was prepared. Together with NCS, the catalyst showed a good activity in acetalization of aldehydes and alcohols. It could be recovered from the reaction mixture by fluorous solid-phase extraction (F-SPE) with excellent purity for direct reuse.

Polymer-supported Pd(0) catalyst for copper- and ligand-free Sonogashira reactions in aqueous media

Abstract The treatment of commercially available polymethyl methacrylate (PMMA) microspheres with palladium (Pd)Cl2 and formaldehyde, generated supported Pd(0)-PMMA with 0.79 (wt)% catalyst loading. The catalyst has been used for copper- and ligand-free Sonogashira reactions in aqueous media. It is highly reactive for the reactions of iodobenzenes with aryl acetylenes or alkyl acetylenes. The performance of the recovered catalyst had no significant difference in five cycles. The Pd leaching was detected at a very low level (2.1–9.8 ppm) for each cycle. PMMA-supported PdCl2, Pd(OAc)2, PdCO3, and PdCl2(MeCN)2 have also been tested for Sonogashira reactions.