Efficient synthesis of an α-trifluoromethyl-α-tosyloxymethyl epoxide enabling stepwise double functionalisation to afford CF3-substituted tertiary alcohols

Copper-Catalyzed Asymmetric Oxidative Desymmetrization of 2-Substituted 1,2,3-Triols

Asymmetric oxidative desymmetrization of 2-substituted glycerols has been achieved by using a new chiral bisoxazoline ligand/copper catalyst system with 1,3-dibromo-5,5-dimethylhydantoin and MeOH. The present transformation smoothly proceeds with readily accessible 2-(hetero)aryl- and alkyl-substituted glycerols and provides straightforward access toward various glycerate derivatives in good to high yields with high enantioselectivities. The synthetic utility of the present protocol was demonstrated by the transformation of the optically active glycerol into a glyceraldehyde derivative.

Practical synthesis of fluorine-containing α- and β-amino acids: recipes from Kiev, Ukraine

Naturally occurring compounds containing a C-F bond are extremely rare; only a handful of fluorine-containing carboxylic acids have been described so far. By contrast, man-made fluorine-containing derivatives of all major classes of biologically important compounds are extremely promising medicinal targets used in the elucidation of biochemical, metabolic transformations and the development of new pharmaceuticals. Among the fluorine-containing derivatives of natural products, fluorinated analogs of amino acids are of particular interest and medicinal potential. This article presents a concise review of various synthetic methods, developed by the Kiev's school of bioorganic chemistry, for the preparation of fluorine-containing analogs of α- and β-amino acids, α-hydroxy acids, amines, as well as their phosphorus and sulfur-derived compounds, in enantiomerically pure form. One of the major methodological goals of the study was practicality, which is understood by us as stereochemical generality, operational convenience and synthetic affordance for each reaction step and isolation of the target products. The synthetic methods developed by our group can be roughly divided in two general categories: fluorine-adaptation of known synthetic approaches and discovery of new reactions. The former approach is most prominently represented by asymmetric homologation of nucleophilic glycine equivalents using fluorinated substrates via alkyl halide alkylations, aldol and Michael addition reactions. A plethora of discovered unexpected reaction outcomes, in particular stereochemical, are emphasized in this review and the particular role of fluorine, in altering the 'normal' reaction result, is explained. The latter direction is notably represented by the novel 1,3-proton shift reaction, a biomimetic reductive amination of fluorinated carbonyl compounds to the corresponding amines and amino acids, as well as the development of α-fluoroalkyl epoxides as true fluorinated synthons for generalized asymmetric synthesis of various biologically relevant compounds. Despite the highly anticipated potential of fluorine-containing amino compounds, their medicinal chemistry still remains underexplored. The major obstacle, in our opinion, is that these selectively fluorinated compounds are generally unavailable to the medicinal chemists for comprehensive, systematic study. We hope this review of synthetic methods will highlight and bring attention to particular types of fluorinated amino acids and related compounds readily available on a laboratory scale using methods developed by our group.

Aryl aminopyrazole benzamides as oral non-steroidal selective glucocorticoid receptor agonists

Aryl aminopyrazole amides capped with N-alkylbenzamides 13-16 are selective glucocorticoid receptor agonists. 2,6-Disubstituted benzamides have prednisolone-like potency or better in vitro. Good oral exposure was demonstrated in the rat, with compounds with lower lipophilicity, for example N-hydroxyethyl benzamides (e.g., 16e).