A continuous-flow synthesis of (–)-oseltamivir composed of five flow units was accomplished. In each unit, the following reactions proceed efficiently: (1) a diphenylprolinol silyl ether mediated Michael reaction, (2) a domino reaction of Michael and intermolecular Horner– Wadsworth–Emmons reactions, (3) protonation, (4) epimerization, and (5) reduction of a nitro group to an amine. (–)-Oseltam...

Since its introduction to the synthetic community in 1984, Garner's aldehyde has gained substantial attention as a chiral intermediate for the synthesis of numerous amino alcohol derivatives. This review presents some of the most successful carbon chain elongation reactions, namely carbonyl alkylations and olefinations. The literature is reviewed with particular attention on understanding how t...

A selective Pd-catalyzed C(3)−H cis-functionalization of piperidine and tetrahydropyran carboxylic acids is achieved using a C(4) aminoquinoline amide auxiliary. High mono- cis-selectivity attained by mesityl acid as an additive. Conditions are developed with significantly lower reaction temperatures (≤50 °C) than other reported heterocycle C(sp3)−H functionalization reactions, which facilitate...

Brassinosteroids represent a class of plant hormones. More than 70 compounds have been isolated from plants. Currently 42 brassinosteroid metabolites and their conjugates are known. This review describes the miscellaneous metabolic pathways of brassinosteroids in plants. There are some types of metabolic processes involving brassinosteroids in plants: dehydrogenation, demethylation, epimerizati...

A family of chiral triazolium salts has been developed for inducing the asymmetric intramolecular Stetter reaction. The use of an aminoindanol-derived catalyst affords optimal results, with the product keto esters formed in 82-97% ee and very good chemical yield. Aromatic and aliphatic aldehydes are equally competent substrates for this reaction. The reaction conditions are reasonably mild and ...

In acidified water solutions of molybdate, aldoses epimerize under the formation of equilibrium mixtures in which the epimer having trans relationship of the hydroxyl groups at C-2 and C-3 predominates. The epimerization of both D-glucose and D-mannose gives the equilibrium mixture of D-glucose and D-mannose in the ratio 75 25. A tentative mechanism for this reaction is suggested and the prepar...

An efficient method has been developed for the salicylaldehyde ester-mediated ligation of unprotected peptides at serine (Ser) or threonine (Thr) residues. The utility of this peptide ligation approach has been demonstrated through the convergent syntheses of two therapeutic peptides--ovine-corticoliberin and Forteo--and the human erythrocyte acylphosphatase protein (∼11 kDa). The requisite pep...

We report that N-(trimethylsilyl)imines serve in the Bis(AMidine)-catalyzed addition of bromonitromethane with a high degree of enantioselection. This allows for the production of a range of protected α-bromo nitroalkane donors (including Fmoc) for use in Umpolung Amide Synthesis (UmAS). Hence, peptide homologation with nonnatural aryl glycine amino acids is achieved in three steps from aromati...

Procyanidin C1 is by far the main flavan-3-ol trimer in cocoa. Like other flavan-3-ols, however, it suffers a lot during heat treatments such as roasting. RP-HPLCHRMS/MS(ESI(-))analysis applied to an aqueous model medium containing commercial procyanidin C1 proved that epimerization is the main reaction involved in its degradation (accounting for 62% of degradation products). In addition to dep...