Palladium-Catalyzed Three-Component Selective Aminoallylation of Diazo Compounds

We describe a Xantphos-containing dinuclear palladium complex-enabled geminal aminoallylation of diazocarbonyl compounds, which selectively provides a range of quaternary α-amino esters. Direct N–H insertion, allylic alkylation of amino nucleophiles, and diene formation were not observed under standard conditions. Mechanistic studies indicated that a relayed pathway via allylation of the N–H insertion product or [2,3]-sigmatropic rearrangement of an ylide intermediate was unlikely

Calculation results for mud shale strain and secant shear modulus under different shear load levels.

Calculation results for mud shale strain and secant shear modulus under different shear load levels.</p

Schematic diagram for comparison of coupling damage.

Schematic diagram for comparison of coupling damage.</p

Fig 6 -

Shear strain curve over time for mud shale under different shear stress levels (a) Sample A1 (axial pressure 1 MPa, impact energy 0 J); (b) Sample A2 (axial pressure 1 MPa, impact energy 1.34 J); (c) Sample A3 (axial pressure 1 MPa, impact energy 2.36 J); (d) Sample A4 (axial pressure 1 MPa, impact energy 3.67 J).</p

Fig 7 -

Comparison between model calculations and test curve (a) Comparison between model calculations and test curve of sample A1 (axial pressure 1 MPa, impact energy 0 J); (b) Comparison between model calculations and test curve of sample A2 (axial pressure 1 MPa, impact energy 1.34 J); (c) Comparison between model calculations and test curve of sample A3 (axial pressure 1 MPa, impact energy 2.36 J); (d) Comparison between model calculations and test curve of sample A4 (axial pressure 1 MPa, impact energy 3.67 J).</p

Schematic diagram for calculation of shear modulus at different moments under a multi-stage creep shear load.

Schematic diagram for calculation of shear modulus at different moments under a multi-stage creep shear load.</p

Parameter inversion results under multi-stage shear creep conditions.

Parameter inversion results under multi-stage shear creep conditions.</p

Related test parameters of shale.

For a long time, one of the important safety problems in open-pit mines is the stability of a large number of high slopes with gently inclined soft interlayer. Rock masses formed after long geological processes generally have some initial damage. Mining works also cause varying degrees of disturbance and damage to rock masses in the mining area during the mining process. This phenomenon means that accurate characterization of the time-dependent creep damage for rock masses under shear load is necessary. The damage variable D is defined based on the spatial and temporal evolution laws of shear modulus and initial level of damage for the rock mass. In addition, a coupling damage equation between the initial damage of the rock mass and shear creep damage is established based on Lemaitre’s strain equivalence assumption. Kachanov’s damage theory is also incorporated to describe the entire process of time-dependent creep damage evolution for rock masses. A creep damage constitutive model that can reasonably reflect the actual mechanical properties of rock masses under multi-stage shear creep loading conditions is established. This takes into account multi-stage shear creep loading conditions, instantaneous creep damage during the shear load phase, staged creep damage and factors influencing the initial damage of rock masses. The reasonableness, reliability and applicability of this model are verified by comparing the results of the multi-stage shear creep test with calculated values from the proposed model. As opposed to the traditional creep damage model, the shear creep model established in this present study takes into account the initial damage of rock masses and can describe the multi-stage shear creep damage characteristics of rock masses more convincingly.</div

Schematic diagram of shear damage evolution for rock masses after considering initial damage.

Schematic diagram of shear damage evolution for rock masses after considering initial damage.</p

Test samples and equipment.

For a long time, one of the important safety problems in open-pit mines is the stability of a large number of high slopes with gently inclined soft interlayer. Rock masses formed after long geological processes generally have some initial damage. Mining works also cause varying degrees of disturbance and damage to rock masses in the mining area during the mining process. This phenomenon means that accurate characterization of the time-dependent creep damage for rock masses under shear load is necessary. The damage variable D is defined based on the spatial and temporal evolution laws of shear modulus and initial level of damage for the rock mass. In addition, a coupling damage equation between the initial damage of the rock mass and shear creep damage is established based on Lemaitre’s strain equivalence assumption. Kachanov’s damage theory is also incorporated to describe the entire process of time-dependent creep damage evolution for rock masses. A creep damage constitutive model that can reasonably reflect the actual mechanical properties of rock masses under multi-stage shear creep loading conditions is established. This takes into account multi-stage shear creep loading conditions, instantaneous creep damage during the shear load phase, staged creep damage and factors influencing the initial damage of rock masses. The reasonableness, reliability and applicability of this model are verified by comparing the results of the multi-stage shear creep test with calculated values from the proposed model. As opposed to the traditional creep damage model, the shear creep model established in this present study takes into account the initial damage of rock masses and can describe the multi-stage shear creep damage characteristics of rock masses more convincingly.</div