Furopyridines. XVIII. Photocycloaddition of furo[2,3-c]pyridin-7(6H)-one with acrylonitrile

The photocycloaddition of furo[2,3-c]pyridin-7(6H)-one ( 1 ) and its N-mefhyl derivative ( 1-Me ) to acrylonitrile has been studied. The structures of the photoadducts isolated by colum chromatography were determined by the nuclear magnetic resonance spectroscopy and single crystal X-ray analysis. The cyclo-addition of 1 afforded an adduct 2 at the carbonyl oxygen and 8-cyano-8,9-dihydrofuro[d]azocin-7(6H)-one ( 3 ), and the addition of 1-Me the N-methyl derivative 3-Me of 3 , (9S*)-9-cyano-6-methyl-3a,7a-dihydro-3a,7a-ethanofuro[2,3-c]pyridin-7(6H)-one ( 4 ), (2S*, 2aR*, 7bR*)- ( 5 ) and (1R*, 2aS*, 7bS*)-2-cyano-3-methyl-4-oxo-1,2,2a,3,4,7b-hexahydrocyclobuta[e]furo[2,3-c]pyridine ( 6 ).     

Catalytic Dehydrogenative Cyclization of o-Teraryls under pH-Neutral and Oxidant-Free Conditions

A cobaloxime-catalyzed acceptorless dehydrogenative cyclization of o-teraryls was developed. In stark contrast to the established methods such as the Scholl or Mallory reactions, this method does not require any strong acids or oxidants, and shows high atom economy and a broad substrate scope. It operates at near room temperature with light as the source of energy. Acid- or oxidant-sensitive functional groups, such as 4-methoxyphenyl, unprotected benzyl alcohol, silyl ether, and thiophene groups are tolerated. Remarkably, aryls with electron-withdrawing groups, and electron-poor heteroarenes, such as pyridine and pyrimidine, can also react. Preliminary mechanistic study reveals that hydrogen gas is released during the reaction, and both light and the cobalt catalyst are important for the dehydrogenation step.     

Catalytic Dehydrogenative Cyclization of o‐Teraryls under pH‐Neutral and Oxidant‐Free Conditions

A cobaloxime‐catalyzed acceptorless dehydrogenative cyclization of o‐teraryls was developed. In stark contrast to the established methods such as the Scholl or Mallory reactions, this method does not require any strong acids or oxidants, and shows high atom economy and a broad substrate scope. It operates at near room temperature with light as the source of energy. Acid‐ or oxidant‐sensitive functional groups, such as 4‐methoxyphenyl, unprotected benzyl alcohol, silyl ether, and thiophene groups are tolerated. Remarkably, aryls with electron‐withdrawing groups, and electron‐poor heteroarenes, such as pyridine and pyrimidine, can also react. Preliminary mechanistic study reveals that hydrogen gas is released during the reaction, and both light and the cobalt catalyst are important for the dehydrogenation step.     

Characterization of the diffusion path in micro- and meso-porous materials from ZLC analysis

It has been demonstrated that the main diffusion paths of micro- and meso-porous UL-zeolites could be characterized from the Zero Length Column (ZLC) desorption curves with an appropriate theoretical analysis (Malekian et al., in Ind. Eng. Chem. Res. 46:5067, 2007). The present work extends this method to study the ZLC desorption data of n-heptane/cumene/mesitylene in three mesoporous SBA-15 samples, 1-methylnaphthalene in MCM-48, cumene in SBA-16 and toluene/cumene in a microporous one-dimensional boron SSZ-42. The investigation results revealed that the structure of SBA-15, MCM-48 and SBA-16 behaved approximately as three-dimensional (isotropic) diffusion system, while SSZ-42 behaved as one-dimensional (anisotropic) diffusion systems. The diffusion path did not change within the measured temperature range, and by using different sorbate molecules. This work confirmed that this effective and relatively inexpensive method can be used as an additional tool for the characterization of porous materials.     

A Short Scalable Route to (−)‐α‐Kainic Acid Using Pt‐Catalyzed Direct Allylic Amination

An increased supply of scarce or inaccessible natural products is essential for the development of more sophisticated pharmaceutical agents and biological tools, and thus the development of atom‐economical, step‐economical and scalable processes to access these natural products is in high demand. Herein we report the development of a short, scalable total synthesis of (?)‐α‐kainic acid, a useful compound in neuropharmacology that is, however, limited in supply from natural resources. The synthesis features sequential platinum‐catalyzed direct allylic aminations and thermal ene‐cyclization, enabling the gram‐scale synthesis of (?)‐α‐kainic acid in six steps and 34 % overall yield.