Asymmetric synthesis of (-)-dehydro--brevicomin with a photoisomerisation-intramolecular acetalisation sequence.

We herein report a novel, short asymmetric synthesis of (-)-dehydro-exo-brevicomin (DHB, 1), a sex pheromone isolated from house mice, in 44% overall yield, the highest yield reported so far, over eight steps from trans-3-hexen-1-ol (7). We successfully prepared the target molecule (-)-1 from spontaneous intramolecular acetalisation after the photoisomerisation of trans-enone 6, which generated the corresponding cis-enone 5in situ, the possible biosynthetic precursor of DHB.

Biomimetic systems involving sequential redox reactions in glycolysis - the sulfur effect.

Magnesium hemithioacetates were used as model cysteine compounds to mimic natural hemithioacetals, and their biomimetic oxidation reactions using a model NAD+ compound were investigated. Cyclic hemithioacetate was found to be the best substrate for the reaction with the model NAD+ compound, which gave the corresponding NADH analog in excellent yield.

Azaspirene analogs inhibit the growth of human uterine carcinosarcoma in vitro and in vivo.

Uterine carcinosarcoma is a highly aggressive gynecological neoplasm that responds poorly to conventional chemotherapy and radiotherapy. Recent studies have shown high angiogenic activities of this tumor, hence anti-angiogenic approaches are expected to provide new treatment strategies for this tumor. In previous work, azaspirene was isolated from Neosartorya sp.

Genetic dissection of pheromone processing reveals main olfactory system-mediated social behaviors in mice.

Most mammals have two major olfactory subsystems: the main olfactory system (MOS) and vomeronasal system (VNS). It is now widely accepted that the range of pheromones that control social behaviors are processed by both the VNS and the MOS. However, the functional contributions of each subsystem in social behavior remain unclear.

Planar-to-planar chirality transfer in the excited state. Enantiodifferentiating photoisomerization of cyclooctenes sensitized by planar-chiral paracyclophane.

Photochemical planar-to-planar chirality transfer was effected by using (R)-[10]paracyclophane-12-carboxylates as a planar-chiral sensitizer and (Z)-cyclooctene and (Z,Z)-1,5-cyclooctadiene as prochiral substrates to give a planar-chiral (E)- and (E,Z)-isomer in up to 44% and 87% enantiomeric excess, respectively, the latter of which being the highest ever reported for a sensitized photochirogenic reaction.

Synthesis and structural revision of phomopsin B, a novel polyketide carrying a 10-membered cyclic-ether ring.

Total synthesis of the proposed structure 2 for phomopsin B was achieved by using an intramolecular olefin metathesis as a key step. The spectral data, however, did not match with those of the natural product reported. Re-examination of the reported NMR data led to the structural revision of phomopsin B to known dothiorelone A 18.

Synthesis of planar-chiral paracyclophanes via samarium(II)-catalyzed intramolecular pinacol coupling.

[reaction: see text] A series of [n]paracyclophanediols (n = 8-12) was synthesized by samarium-catalyzed pinacol coupling for their ansa-bridge formation. Enantiomerically pure [n]paracyclophane esters were derived from the diols in a several steps via chiral resolution (for n = 10) or via crystallization-induced asymmetric transformation (for n = 11) by using amino alcohol auxiliaries and their selective cleavages.

Biomimetic Oxidation of Aldehyde with NAD Models: Glycolysis-Type Hydrogen Transfer in an NAD /NADH Model System.

Just like in biological systems, the GAPDH-catalyzed oxidation of aldehyde to carboxylate proceeds in conjunction with 1,4-selective reduction of NAD to NADH model compounds [Eq. (1)]. The combination of GAPDH- and LDH-type transfer reactions is also described here as a system mimic for the NAD /NADH redox cycle in anaerobic glycolysis.