Asymmetric addition of organozinc compounds to carbonyl groups is one of the most useful methods for the synthesis of alcohols with high enantioselectivity. There is a wide range of chiral catalysts, although their synthesis requires more than one step and not often readily available starting materials. In this work, chiral β-hydroxy oxazolines derived from (+)-camphor and (-)-fenchone were easily synthesized through a one-step method, with good yields. Both ligands were evaluated as catalysts for the stereoselective addition of diethylzinc to aromatic aldehydes. All ligands showed good catalytic activity, leading both to the preparation of the R enantiomer of chiral secondary alcohols. As ligand 2 provided slightly better enantioselectivities, it was used as chiral inductor for the addition of diethylzinc for a larger number of aldehydes, resulting in good to excellent yields (88-98%) and enantiomeric excess up to 96%.

β-Hidroxi-2-oxazolinas quirais foram sintetizadas e avaliadas como catalisadores na adição de dietilzinco a aldeídos. Todas as oxazolinas se mostraram eficientes na obtenção dos produtos de adição. Os melhores excessos enantioméricos (69 a 78%) foram obtidos quando se empregou a β-hidroxi oxazolina quiral derivada da (−)-mentona e do amino álcool 2-amino-2-metilpropan-1-ol.

Chiral β-hydroxy-2-oxazolines were synthesized and evaluated as catalysts for the addition of diethylzinc to aldehydes. All oxazolines proved effective in obtaining the addition products. The best enantiomeric excesses (69-78%) were obtained using the chiral β-hydroxy oxazoline derived from (−)-menthone and the amino alcohol 2-amino-2-methylpropan-1-ol.

A composição dos voláteis emitidos por diferentes árvores é usada com sucesso como marcador em uma grande variedade de estudos, como a quimiotaxonomia. A caracterização dos voláteis emitidos por diferentes espécies de Pinus provou ser uma ferramenta importante para entender o processo de seleção de plantas hospedeiras por insetos herbívoros. Os voláteis dos galhos de cinco espécies de Pinus (P. caribaea, P. elliottii, P. maximinoi, P. patula e P. taeda) foram coletados por aeração e analisados por cromatografia gasosa com detector de ionização de chama (GC-FID), utilizando colunas de fase não-polar e quiral, e espectrometria de massas (GC-MS) com analisador de quadrupolo. A composição relativa foi usada para análises de componentes principais (PCA) e de agrupamento hierárquico (HCA) para a discriminação das cinco espécies.

The composition of the volatiles emitted by different trees has been successfully used as a marker in a wide variety of studies, such as chemotaxonomy. Characterization of the volatiles emitted by different species of Pinus has proven to be an important tool to understand the process of host-tree selection by herbivorous insects. The volatiles present in samples of the branches of five species of Pinus (P. caribaea, P. elliottii, P. maximinoi, P. patula and P. taeda) were collected by aeration, and the contents analyzed by gas chromatography using a flame ionization detector (GC-FID), applying non-polar and chiral column phases, and mass spectrometry (GC-MS) using a quadrupole mass analyzer. The relative composition of the different volatiles was used to perform a discriminant analysis among the five pine species, by means of cluster (HCA) and principal component (PCA) analyses.

O gorgulho-da-casca-do-pinus, Pissodes castaneus (De Geer, 1775) (Coleoptera, Curculionidae) é uma praga florestal que foi detectada no Brasil em 2001 e atualmente se encontra distribuída nos três estados da Região Sul, causando grande preocupação para o setor florestal. Os objetivos deste estudo foram isolar, identificar e avaliar a atividade comportamental dos voláteis produzidos pelos machos de P. castaneus. Nossos resultados indicam que a comunicação entre indivíduos desta espécie é mediada por feromônios, o que foi evidenciado pela atração significativa de fêmeas pelos voláteis produzidos pelos machos. Testes comportamentais realizados com os insetos e sua planta hospedeira, Pinus taeda, indicam que os compostos produzidos pelos machos atuam como feromônios sexuais e que os compostos liberados pela planta hospedeira não aumentam a atividade destes compostos. Os compostos produzidos pelos machos de P. castaneus foram identificados como (1R, 2S)-grandisal e (1R, 2S)-grandisol, em excesso enantiomérico superior a 95%.

The banded pine weevil, Pissodes castaneus (De Geer, 1775) (Coleoptera, Curculionidae) is a forest pest recorded in Brazil since 2001, which is already distributed in the three states of the Southern Region, causing great concern to the forestry sector. Objectives of our study were to isolate, identify, and assess the behavioral activity of male-produced volatiles of P. castaneus. Our results indicate that communication between conspecifics of P. castaneus is mediated by pheromones, as verified by the significant attraction of females to male-produced volatiles. Behavioral tests performed with the insects and the host plant, Pinus taeda, showed that male-produced compounds may act as sex pheromones and that the compounds released by the host plant did not enhance the activity of the male-produced volatiles. The chemical structures of the male specific volatile compounds produced by P. castaneus were determined to be (1R, 2S)-grandisal and (1R, 2S)-grandisol in an enantiomeric excess exceeding 95%.