This article describes the development of microwave-assisted oxyanionic 5-exo-dig cyclization-Claisen rearrangement sequence as a convenient "one-pot" route to a variety of seven-membered carbocyclic ring systems. This process was used as the key transformation for the construction of several natural products, including frondosins A, B, and C.

Claisen rearrangement reaction was employed for the first time to obtain a novel PPTA bearing reactive allyl and hydroxyl groups which may act as a sizing agent of Kevlar fibers to improve the interface structure and interfacial adhesion of rubber or epoxy based composites.

Arylsulfinyl groups direct the metal-free, regiospecific, nucleophilic ortho-allylation of pyrroles and pyrazoles. Mechanistic studies support the intermediacy of allylsulfonium salts that undergo facile thio-Claisen rearrangement onto the heterocyclic ring, giving products of coupling. The strategy has been adapted to allow regiospecific propargylation of the heterocyclic substrates.

A novel and efficient approach to 3-allyl-chromones from alkynones and allylic alcohols via a tandem Michael addition-Claisen rearrangement-O-arylation reaction has been developed. Diversely structural 3-allyl-chromones were afforded in up to 93% yield for 24 examples. This synthetic strategy is regiospecific, highly efficient, environment friendly and metal-free.

The Johnson-Claisen rearrangement of D-gluco and L-ido-derived allylic orthoesters afforded gamma,delta-unsaturated ester that on ester reduction, epoxidation, regioselective oxirane opening by sodium azide and hydrogenation led to sugar amino alcohols--immediate precursors for 1-deoxy-homonojirimycin 3a,b, and polyhydroxylated homoazepanes 4a,b. Our synthetic approach and glycosidase inhibitor...

Attempted RCM of 2,2'-bis(allyloxy)-1,1'-binaphthyl resulted in a Claisen-type rearrangement of a postulated labile dioxacyclodecine proceeding at room temperature and followed by [2+2] cycloaddition. Structures of products were confirmed by X-ray crystallography. A mechanistic rationalisation based on relative stabilities of proposed intermediates and transition states is provided.

γ-aminobutiric acid (gaba), the major inhibitory neurotransmitter in the central nervous system is activated by the antispastic and muscle relaxant agent, baclofen, which is a lipophilic derivative of gaba. because of its biological and pharmacological importance, there are several reports in the literature about the synthesis of baclofen since 1962. in this study baclofen was easily synthesize...