No abstract

No abstract

This review article describes the use of some of the most popular chiral auxiliaries in the asymmetric synthesis of biologically active compounds. Chiral auxiliaries derived from naturally occurring compounds, such as amino acids, carbohydrates, and terpenes, are considered essential tools for the construction of highly complex molecules. We highlight the auxiliaries of Evans, Corey, Yamada, Enders, Oppolzer, and Kunz, which led to remarkable progress in asymmetric synthesis in the last decades and continue to bring advances until the present day.

Anilides 4d, 4e, 4 g, and 4 h are promising candidates for the development of novel herbicides. According to in silico studies, they inhibit histone deacetylase in plants, which can be exploited for the development of new weed control methods. © 2018 Society of Chemical Industry.

The stereoselective total synthesis of (+)-epi-cytoxazone was performed satisfactorily in 8 steps, in 17% overall yield, via a novel route from 2,3-O-(3-pentylidene)-(R)-glyceraldehyde. The bulky group alkene-ketal allowed intramolecular control of the target molecule's asymmetric centers in the dihydroxylation step by promoting the approach of OsO 4 to the face opposite to that of the ketal group.

No abstract

No abstract

This study describes the stereoselective synthesis of two new γ-lactones in 6 and 3 steps and 19 and 32% yield, respectively, directed toward the total synthesis of the natural product (−)-cleistenolide. The starting material was an enantiomerically pure diacetonide diol, derived from d-mannitol with the required stereocenters for (−)-cleistenolide synthesis. γ-Lactone syntheses were based on highly selective protection and deprotection of hydroxyls from d-mannitol. The formation of γ-lactone rings was the culmination of this approach, made possible by a Horner-Wadsworth-Emmons Z-olefination between diacetal aldehyde and ethyl 2-(bis(o-tolyloxy)phosphoryl)acetate to produce an unsaturated ester. The Z-isomer ester was highly favored in relation to the E-isomer (Z/E ratio of 94:6), allowing the formation of the γ-lactone ring under acid catalysis. This strategy precluded the use of chiral auxiliaries or catalysts for the control of stereocenters in the novel γ-lactones.