Photoredox/Ti dual-catalyzed dehydroxylative ring-opening Giese reaction of cyclobutanone oximes

A dehydroxylative ring-opening Giese reaction of cyclobutanone oximes enabled by photoredox/Ti dual catalysis has been reported in this work.This protocol avoids the prefunctionalization of oximes and the use of stoichiometric triarylphosphine reagents.It also features mild conditions,broad substrate scope and good functional group tolerance.The gram-scale reaction,product derivatization,late-stage functionalization of complex pharmaceutical and natural product derivatives,and oligopeptide modification exhibit the potential application of this methodology in synthetic chemistry.

Activating Process of Geopolymer Source Material: Kaolinite

The calcining process was recorded by differential scanning calorimetry and ther-mogravimetry （DSC-TG）. The dehydroxylation （activating process） was partitioned into two steps by calculating and comparing the O-H bond lengths between inner hydroxyl group and surface hydroxyl group, as well as the ionic bond of Al-OH and position of -OH. X-ray diffraction （XRD） and compressive strength measurement show that the activity of calcined materials increases with the increasing of temperature in dehydroxylation region but decreases abruptly in the ＂spinel＂ region. The suggested temperature for activating kaolinite is 900 ℃ .

Dehydroxylation of Glycerol on Pt Surfaces:Ab Initio Molecular Dynamics Study

Glycerol is an important raw material in the chemical industry,and dehydroxylation of glycerol would produce 1,2-propanediol and 1,3-propanediol.Here we studied glycerol dehydroxylation with ab initio molecular dynamics simulations on Pt(111)and Pt(211)surfaces at 453 K.The free energies obtained on Pt show that dehydroxylation is more likely to occur at the terminal carbon than the central carbon,and 1,2-propanediol would be produced preferentially,which is consistent with the selectivity observed experimentally.We found a linear relationship between the free energy barrier and the difference of average distances between O atoms at the initial state and transition state.Although a high correlation between the stability of gaseous glycerol and the number of formed hydrogen bonds is determined from density functional theory calculations,the hydrogen bonds formed within surface structures play a negligible role in determining the free energy barriers of dehydroxylation.

Special Chiral C_(2)-Symmetric endo-Biarylnorbornane: Synthesis and Structure Illustration

A highly efficient and practical synthesis for strained special scaffold of chiral endo-biarylnorbornane starting from available norbornadione was achieved with direct stereoselective dehydroxylation of tertiary alcohol as the key step,and the structure was illustrated by X-ray structural analysis.