A concise total synthesis of the antiproliferative macrolide (+)-neopeltolide has been completed, utilising a Jacobsen hetero Diels-Alder reaction to install the trisubstituted tetrahydropyran ring.

(+/-)-Neovibsanin B was synthesized based on a DMI-accelerated intramolecular Diels-Alder reaction followed by oxy-Michael addition-lactonization. The synthetic (+/-)-neovibsanin B induced similar morphological changes in NGF-mediated PC12 cells compared with natural (+)-neovibsanin B.

We provide the first detailed time-resolved mechanistic information on the protonation of a model of the subsite of [FeFe]-hydrogenase, [Fe2(mu-pdt)(CO)4(PMe3)2]; the deceptively simple stoichiometric reaction is shown to be limited by the rate of protonation of the basal-apical isomer followed by its rearrangement to the transoid basal form.

We have successfully developed a novel and efficient phosphine-catalyzed sequential [2+3] and [3+2] annulation reaction of γ-substituent allenoates to construct bicyclic[3, 3, 0]octene derivatives. The protocol uses readily available γ-substituent allenoates as the starting materials, inexpensive PBu3 as the catalyst, and the corresponding products were obtained in good to excellent yields unde...

High diastereoselectivity is observed in the preparation of configurationally stable allocolchicinoids 5 from Fischer carbene complexes 4 and 1-pentyne. The analogous reaction of complexes 8 gives 9 with moderate diastereoselectivity for the opposite atropisomer and this selectivity can be taken to high levels under thermodynamic conditions.

The development of an efficient method for the construction of biologically relevant sultams is described, which represents the first case of cobalt-promoted C-H/N-H functionalization of sulfonamides with allenes. This newly developed annulation reaction demonstrated good functional group tolerance and excellent regioselectivity. Both terminal monosubstituted allenes and internal disubstituted ...

The photochemistry of the pyrazolo[1,2-a]benzotriazole 1b and its dimethyl derivative 1c was studied in argon matrices at 12 K and in solution at 190 K. On irradiation at 365 nm, 1b and 1e undergo ring closure to yield the triazasemibullvalenes 2b and 2c, respectively, which were identified unambiguously by NMR and IR spectroscopy. This novel type of cyclization is reversed on warming or by irr...

Six Korea high oil (KHO) corn varieties varying in germ and endosperm size and oil content (4-21%, wet basis) were subjected to three sequential combinations of milling (M), germ separation (S), fermentation (F), and in situ transesterification (T) to produce bioethanol and biodiesel. Production parameters including saccharification, bioethanol yield, biodiesel yield and composition, and conver...

The cyclizations of two structurally similar 2-oxo-5-hexenyl-type radicals have been investigated by ab initio and density functional (UB3LYP/6-31+G**//UHF/6-31G* and UB3LYP/6-31G*//UB3LYP/6-31G*) calculations. The origin of apparently contradictory reports of 6-endo and 5-exo cyclizations is determined. Kinetic control favors 6-endo cyclization, while thermodynamic control gives 5-exo cyclizat...

The coupling reaction of 4-chloro-1H-imidazo[4,5-c]pyridine (6-chloro-3-deazapurine, 3) with several cyclopentyl derivatives under Mitsunubo reaction conditions provides an efficient entry into N-7 and N-9 substituted 3-deazapurine carbocyclic nucleosides of antiviral potential. The versatility of this procedure is illustrated with a new and efficient synthesis of (K)-3-deazaaristeromycin, a fo...