A chemoenzymatic synthesis of sialic acid from inexpensive N-acetyl-D-glucosamine is described. In a three-step Wittig-protection-ozonolysis strategy manno-configured aldehydes are obtained. Treatment with oxaloacetate in the presence of macrophomate synthase affords the signature α-keto-γ-hydroxy acid moiety with high diastereoselectivity.

Ultrasonic irradiation in the presence of ozone is demonstrated to be effective for the rapid oxidation of oxalic acid, bioxalate, and oxalate (H(2)C(2)O(4)/HC(2)O(4)(-)/C(2)O(4)(2-)) in aqueous solution to CO(2) and H(2)O. The degradation rate of bioxalate exposed to "sonozone" (i.e., simultaneous ultrasonication and ozonolysis) was found to be 16-times faster than predicted by the linear addi...

Methacrolein oxide (MACR-oxide) is a four-carbon, resonance-stabilized Criegee intermediate produced from isoprene ozonolysis, yet its reactivity not well understood. This study identifies the functionalized hydroperoxide species, 1-hydroperoxy-2-methylallyl formate (HPMAF), generated reaction of MACR-oxide with formic acid using multiplexed photoionization mass spectrometry (MPIMS, 298 K = 25 ...

The preparation of an advanced intermediate toward the enantioselective synthesis of tetrodotoxin is outlined. The enantiomerically pure cyclopentene 15 was generated from ketone 14 by alkylidene carbene insertion with retention of absolute configuration. An ozonolysis/aldol sequence first produced the trans cyclohexenone, which upon epimerization gave the more stable cis enone 18.

9-Aminononanoic acid, 9-aminononanamide, and related compounds derived from soybean oil by reactions, including reductive ozonolysis and reductive amination, were separated on an analytical scale either by gas liquid chromatography of trifluoroacetylated or trimethylsilylated derivatives or by thin layer chromatography and on a preparative scale by ion-exchange chromatography. Comparative analy...

Well-defined ferrocene-containing triblock copolymers were synthesized by atom transfer radical polymerization and self-assembled into highly ordered hexagonal arrays of cylinders via solvent annealing. The thin films were further used as a template and converted into highly ordered iron oxide nanoparticles (α-Fe2O3) by UV/ozonolysis and thermal pyrolysis.

The preparation of Kyn-containing peptides is difficult, owing to the low reactivity of Kyn in the coupling reaction. In this report, Kyn-containing peptides were efficiently obtained via on-resin ozonolysis of the corresponding Trp-containing peptide. In addition, a Kyn-containing cyclic peptide, cyclomontanin B, has been synthesized by this strategy in the combination with serine/threonine li...

The preparation of the crystalline amide 2 is reported. Conjugate addition to 2 proceeded with the expected high diastereocontrol to give 3. This set the stage for subsequent intramolecular alkylidene C-H insertion to give, after ozonolysis and aldol condensation, (-)-mesembrine 1. Amide 2 should be a useful chiron for the enantioselective construction of cyclic quaternary centers.

An efficient one-pot synthesis of optically active β-alkyl-substituted alcohols through a tandem coppercatalyzed asymmetric allylic alkylation (AAA) with organolithium reagents and reductive ozonolysis is presented. Furthermore, hydroboration−oxidation following the Cucatalyzed AAA leads to the corresponding homochiral γalkyl-substituted alcohols.