Synthesis Of Medium-ring Lactones Research Articles

Synthesis of medium-sized lactones from siloxy alkynes via ring expansion

Synthesis of medium ring lactones remains as a challenging topic in organic synthesis due to the disfavored kinetic and thermodynamic features. Herein we detail an efficient intermolecular process using siloxy alkynes as substrates and oxetene ring expansion as the key strategy. With extension to a new silyl-masked alkyne, this reaction now features a broad scope, high efficiency, and mild conditions.

Métodos de preparação de lactonas de anel médio

There are several natural products bearing medium ring lactone moieties, which are those containing a ring size in the range of 8 to 11 members. This review intends to cover the last 10 years (1996-2005) of the literature concerning the synthesis of medium ring lactones.

Synthesis of medium-ring lactones via tandem methylenation/Claisen rearrangement of cyclic carbonates

Tandem methylenation/Claisen rearrangement of cyclic carbonates derived from vinyl-substituted 1,3- and 1,4-diols afforded eight and nine-membered unsaturated lactones respectively.

Intramolecular Diels–Alder reaction of functionalized trienes: synthesis of medium-ring lactones †

A simple preparative procedure has been developed for trienic systems, starting from cyclic α,β-unsaturated acetals derived from crotonaldehyde and (E)-pent-2-enal. The reaction is initiated by a regioselective metallation at the γ site of the unsaturated system that immediately induces 1,4-eliminative ring fission, and stereoselectively affords hydroxy-functionalized E-1,3-dienes. The esterification of those hydroxy dienes with acryloyl chloride gives activated trienes, suitable for intramolecular Diels–Alder reaction that yields medium-ring lactones. This method is relatively versatile with respect to the length and the substitution of the tether between the diene and the dienophile. The presence of additional stereogenic centres in the tether induces interesting selectivities during the cycloaddition step that are reported and discussed.