Gustavo A. Kashiwagi

Previously, a method for the activation of thioglycosides and thioimidates using benzyl trichloroacetimidate in the presence of triflic acid has been introduced. Good yields were achieved with highly reactive substrates, whereas the efficiency of reactions with less reactive glycosyl donors and/or acceptors remained modest. Reported herein is the development of a significantly improved method for the activation of thioglycosides using p-methoxybenzyl trichloroacetimidate or diphenylmethyl trichloroacetimidate in the presence of catalytic triflic acid. Excellent yields were achieved with all tested substrates, and the reaction conditions were found to be compatible with chemoselective and selective activation strategies for multistep glycan synthesis.

Reported herein is a new HPLC‐based automated synthesizer (HPLC−A) capable of a temperature‐controlled synthesis and purification of carbohydrates. The developed platform allows to perform various protecting group manipulations as well as the synthesis of O‐ and N‐glycosides. A fully automated synthesis and purification was showcased in application to different carbohydrate derivatives including glycosides, oligosaccharides, glycopeptides, glycolipids, and nucleosides.

The reverse orthogonal strategy was invented in 2011 in an attempt to address drawbacks of other strategies for glycan assembly. Different from the classical orthogonal approach that relies on the orthogonality of leaving groups, the reverse strategy is based on orthogonal protecting groups that could be removed during the glycosylation step. This strategy remained largely unexplored due to only one combination of orthogonal protecting groups that would fit into this concept. Reported herein are new orthogonal combinations of leaving and protecting groups that help to streamline the glycan assembly. Also reported is further refinement of the previously reported reaction conditions.

Aedes aegypti(L.) (Diptera: Culicidae) is one of the main vectors of arboviruses, including dengue, Zika, and chikungunya. It almost exclusively inhabits urban areas. Both sexes feed on plant carbohydrates, although for males, this is their only food source. In the case of floral nectars, mosquitoes locate plant sugar sources assisted by volatile compounds. In this work, we found that the floral scent ofSenecio madagascariensiselicited a behavioral response in males; therefore, we focused on identifying the volatiles emitted by these flowers. The terpenes (±)-α-pinene, β-pinene, sabinene, and phellandrene and 1-alkenes 1-undecene, and 1-nonene were identified. To determine which compounds are bioactive, pure synthetic lures were assessed using an olfactometer. Only the main compound 1-nonene was an attractant for males. Since our goal was the introduction of synthetic floral-based attractants in toxic sugar-baited traps, we formulated 1-nonene in solid paraffin and stearin matrices to obtain a controlled release system. The bioassay with a toxicological end point showed that the incorporation of a feeding attractant to the toxic sugar trap increased overall mortality. These results suggest that it is possible to use plant volatile compounds or flower cuttings as maleAe. aegyptiattractants to improve the efficacy of baited traps.

This review aims to highlight common issues involved in the assembly of 1,2‐linked oligosaccharides. There is extensive literature on the subject, but most of the publications only address general oligosaccharides. Construction of 1,2‐glycosidic linkage has an additional and intrinsic complexity due to its glycosylated O‐2 position. Elongation of the fragment from reducing end curtails the possibility of using O‐2 participating groups in the donor. The 2‐O‐glycosylated donors used in this context or in a convergent approach lead to the principal stereocontrol loss when 1,2‐trans gluco type or manno type linkage are targets. Only non‐reducing end elongation strategy can ensure 1,2‐trans linkage, but following a more expensive and cumbersome route. Archetypical cases where the convergent approach drove to a stereocontrol loss are presented. The perspective of this analysis attempts to complement Paulsen, Boons and Demchenko's masterworks about strategies in oligosaccharides synthesis.