Organocatalyzed Direct Glycosylation of Unprotected and Unactivated Carbohydrates

Organocatalyzed direct glycosylation of unprotected and unactivated carbohydrates is reported. This process is catalyzed by triphenylphosphine and tetrabromomethane at room temperature under neutral conditions. With this operationally simple protocol thermodynamically favored, glycosides were obtained in a very straightforward reaction

Isoleucine-Catalyzed Direct Asymmetric Aldol Addition of Enolizable Aldehydes

Isoleucine-catalyzed direct enantioselective aldol additions between enolizable aldehydes are reported. Intermediate acetal structures dictate the configurative outcome and were supported by a hydrogen bond. This direct isoleucine-catalyzed aldol addition represents a welcome complement to both proline- and histidine-catalyzed aldol additions of enolizable aldehydes

Histidine-Catalyzed Asymmetric Aldol Addition of Enolizable Aldehydes: Insights into its Mechanism

Extensive studies of asymmetric cross-aldol addition between enolizable aldehydes are described and provide a deeper insight into histidine-catalyzed aldol additions. In particular, aspects of enantio- as well as diastereoselectivity of these reactions are discussed. Rules and predictions of configurative outcome are explained by using different transition-state models. These discussions are confirmed by extensive computations

Histidine-Catalyzed Asymmetric Aldol Addition of Enolizable Aldehydes: Insights into its Mechanism

Extensive studies of asymmetric cross-aldol addition between enolizable aldehydes are described and provide a deeper insight into histidine-catalyzed aldol additions. In particular, aspects of enantio- as well as diastereoselectivity of these reactions are discussed. Rules and predictions of configurative outcome are explained by using different transition-state models. These discussions are confirmed by extensive computations

Four into One: Organocatalyzed Stereoselective Conjugate Addition of Unprotected and Unactivated Carbohydrates

This paper proposes a new and stereoselective access to glycosides. This operationally simple approach achieved via base-catalyzed conjugate additions of unprotected and unactivated carbohydrates to activated alkenes or alkynes is described

Multicomponent Cascade Reactions of Unprotected Ketoses and Amino Acids – Access to a Defined Configured Quaternary Stereogenic Center

A highly stereoselective multicomponent cascade reaction of ketones with unprotected amino acids was developed. This operationally simple methodology was expanded to reactions of unprotected ketohexoses and unprotected amino acids. By the careful choice of amino acid and isonitrile, an optional access to all possible enantiomers is given

Decarboxylative Cascade Reactions of Dihydroxyfumaric Acid: A Preparative Approach to the Glyoxylate Scenario

An operationally simple protocol is reported to generate an α-hydroxyacyl anion by the decarboxylation of dihydroxyfumaric acid. To date, the “missing” utilization of the hydroxyacyl anion in highly chemo- and stereoselective cascade reactions enables short and direct construction of carbohydrates