Regioselectivity in arene-catalyzed reductive lithiation of acetals of chlorobenzaldehydes

The regioselectivity of arene-catalyzed reductive lithiation of acetals of chlorobenzaldehydes strongly depends on the form of lithium metal employed as a reducing agent. According to previous findings, naphthalene catalyzed reductions run in the presence of lithium powder (high Na content) led to competitive metalations of both aromatic carbon-chlorine and benzylic carbon-oxygen bonds. At variance with these results, naphthalene catalyzed reductions run in the presence of lithium wire (either high or low Na content) led to highly regioselective metalation of aromatic carbon-chlorine bonds. These results disclose new possibilities of selective applications of arene-catalyzed reductive lithiation reactions. (c) 2005 Elsevier Ltd. All rights reserved

Brindley’s Glands Volatilome of the Predator Zelus renardii Interacting with Xylella Vectors

Alien species must adapt to new biogeographical regions to acclimatise and survive. We consider a species to have become invasive if it establishes negative interactions after acclimatisation. Xylella fastidiosa Wells, Raju et al., 1986 (XF) represents Italy’s and Europe’s most recent biological invasion. In Apulia (southern Italy), the XF-encountered Philaenus spumarius L. 1758 (Spittlebugs, Hemiptera: Auchenorrhyncha) can acquire and transmit the bacterium to Olea europaea L., 1753. The management of XF invasion involves various transmission control means, including inundative biological control using Zelus renardii (ZR) Kolenati, 1856 (Hemiptera: Reduviidae). ZR is an alien stenophagous predator of Xylella vectors, recently entered from the Nearctic and acclimated in Europe. Zelus spp. can secrete semiochemicals during interactions with conspecifics and prey, including volatile organic compounds (VOCs) that elicit conspecific defence behavioural responses. Our study describes ZR Brindley’s glands, present in males and females of ZR, which can produce semiochemicals, eliciting conspecific behavioural responses. We scrutinised ZR secretion alone or interacting with P. spumarius. The ZR volatilome includes 2-methyl-propanoic acid, 2-methyl-butanoic acid, and 3-methyl-1-butanol, which are consistent for Z. renardii alone. Olfactometric tests show that these three VOCs, individually tested, generate an avoidance (alarm) response in Z. renardii. 3-Methyl-1-butanol elicited the highest significant repellence, followed by 2-methyl-butanoic and 2-methyl-propanoic acids. The concentrations of the VOCs of ZR decrease during the interaction with P. spumarius. We discuss the potential effects of VOC secretions on the interaction of Z. renardii with P. spumarius

Preparation of 4-arylthiazol-2(3H)-ones and the three-component synthesis of multidentate 5,5’-methylenebis[4-arylthiazol-2(3H)-one] ligands

The synthesis of 4-arylthiazol-2(3H)-ones is reported employing a novel and mild methodology using benign solvents. In a second objective the multicomponent preparation of 5,5’-methylenebis[4-arylthiazol-2(3H)-ones] is described following the same strategy. The analysis of the mechanism is also studied and confirmed using chemical tests.We gratefully acknowledge financial support from Çukurova University (Project no: TSA-2021-13814), Mersin University (Project no. 2020-1-AP4-3982) and by the University of Alicante (VIGROB-068, UAUSTI21-05). We gratefully acknowledge financial support from the Spanish Ministerio de Ciencia, Innovación y Universidades (project RED2018-102387-T) the Spanish Ministerio de Economía, Industria y Competitividad, Agencia Estatal de Investigación (AEI) and Fondo Europeo de Desarrollo Regional (FEDER, EU) (project PID2019-107268GB-I00), the Generalitat Valenciana (IDIFEDER/2021/013, CIDEGENT/2020/058). JFO thanks Medalchemy S.L and the University of Alicante (UAIND19) for a predoctoral contract

Polyfunctional lithium organometallics for organic synthesis

Multifunctional organic molecules can be achieved by reacting functionalized organolithium compounds with electrophilic reagents, this fact making these intermediates of relevant interest in synthetic organic chemistry. Another remarkable fact concerning organolithium compounds, compared with other organometallic compounds, is that they can be prepared following a great number of diferent methodologies: hydrogen-lithium exchange (deprotonation), halogen-lithium exchange, transmetallation reactions, carbon-heteroatom bond cleavage and carbolithiation of multiple carbon-carbon bonds. However, the highly ionic character of the carbon-lithium bond makes these compounds extremely reactive and also unstable, so the synthetic processes should be carried out in some cases under very mild reaction conditions