Origins of Stereoselectivities of Dihydroxylations of <i>cis</i>-Bicyclo[3.3.0]octenes

Stereoselectivities of the dihydroxylations of <i>cis</i>-bicyclo­[3.3.0]­octene intermediates for a projected total synthesis of chromodorolide A have been explored experimentally. The reaction occurs unexpectedly on the apparently more hindered (concave) face; this result has been explained through computational studies using B3LYP and B3LYP-D3 methods. Torsional effects are largely responsible for the stereoselectivity encountered in the chromodorolide A synthesis. Many literature examples have been reported on related cases. QM calculations show that the stereoselectivities of dihydroxylations of fused cyclopentenes are influenced by the conformational rigidity or flexibility of the substrate. Torsional, electrostatic, and steric effects can all influence stereoselectivity, and the rigidity or flexibility of conformations of reactants provides a predictive guide to stereoselectivity

From sago to rice, from forest to town: the consequences of sedentarization for the nutritional ecology of Punan former hunter-gatherers of Borneo

The first total synthesis of a chromodorolide marine diterpenoid is described. The core of the diterpenoid is constructed by a bimolecular radical addition/cyclization/fragmentation cascade that unites two complex fragments and forms two C–C bonds and four contiguous stereogenic centers of (−)-chromodorolide B in a single step. This coupling step is initiated by visible-light photocatalytic fragmentation of a redox-active ester, which can be accomplished in the presence of an iridium or a less-precious electron-rich dicyanobenzene photocatalyst, and employs equimolar amounts of the two addends. Computational studies guided the development of this central step of the synthesis and provide insight into the origin of the observed stereoselectivity

Total Synthesis of (−)-Chromodorolide B By a Computationally-Guided Radical Addition/Cyclization/Fragmentation Cascade

The first total synthesis of a chromodorolide marine diterpenoid is described. The core of the diterpenoid is constructed by a bimolecular radical addition/cyclization/fragmentation cascade that unites two complex fragments and forms two C–C bonds and four contiguous stereogenic centers of (−)-chromodorolide B in a single step. This coupling step is initiated by visible-light photocatalytic fragmentation of a redox-active ester, which can be accomplished in the presence of an iridium or a less-precious electron-rich dicyanobenzene photocatalyst, and employs equimolar amounts of the two addends. Computational studies guided the development of this central step of the synthesis and provide insight into the origin of the observed stereoselectivity

Variables of RumiWatch noseband sensors and 3D-accelerometers (RumiWatch, ITIN+HOCH GmbH, Fütterungstechnik, Liestal, Switzerland).

<p>Variables of RumiWatch noseband sensors and 3D-accelerometers (RumiWatch, ITIN+HOCH GmbH, Fütterungstechnik, Liestal, Switzerland).</p

Schematic representation of the experimental procedure per study group.

<p>Accelerometers and noseband sensors (RumiWatch-units = RWU) are either attached (light grey) or attached and data recorded (dark grey). Video recording (VR) procedures used for habituation of study cows to the procedure are marked in light grey, VR used for lameness assessment are marked in dark grey. AS = Animal Selection, CE = clinical examination, AO = animal observation (heat, illness, gait scoring), FE = foot examination in the trimming chute.</p

Variables of RumiWatch noseband sensors and accelerometers (RumiWatch, ITIN+HOCH GmbH, Fütterungstechnik, Liestal, Switzerland) of non-lame (group C) and lame cows (group L).

<p>Variables of RumiWatch noseband sensors and accelerometers (RumiWatch, ITIN+HOCH GmbH, Fütterungstechnik, Liestal, Switzerland) of non-lame (group C) and lame cows (group L).</p

Receiver operating characteristics (ROC) curves of different logistic regression models to discriminate between lame (NRS ≥ 2.5) and non-lame cows (NRS ≤ 2).

<p>First model (-∙-) includes standing bouts (AUC = 0.81), second model (─) includes walking speed_calc (AUC = 0.88); third model (- -) includes walking speed_calc and the number of standing bouts (AUC = 0.96); fourth model (∙∙∙) includes walking speed_calc, the number of standing bouts and the eating time (AUC = 0.96). NRS = numerical rating system according to Flower and Weary [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0155796#pone.0155796.ref038" target="_blank">38</a>]. AUC = area under the receiver operating characteristics curve.</p

Results of univariable logistic regression and receiver operating characteristics analysis of a cow being lame (numerical rating system according to Flower and Weary [38], NRS ≥ 2.5) using different RumiWatch noseband sensor and accelerometer (RumiWatch, ITIN+HOCH GmbH, Fütterungstechnik, Liestal, Switzerland) variables as predictors on the cutoff value with highest sensitivity + specificity.

<p>Results of univariable logistic regression and receiver operating characteristics analysis of a cow being lame (numerical rating system according to Flower and Weary [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0155796#pone.0155796.ref038" target="_blank">38</a>], NRS ≥ 2.5) using different RumiWatch noseband sensor and accelerometer (RumiWatch, ITIN+HOCH GmbH, Fütterungstechnik, Liestal, Switzerland) variables as predictors on the cutoff value with highest sensitivity + specificity.</p

Clinical variables of non-lame (group C) and lame (group L) cows.

<p>Clinical variables of non-lame (group C) and lame (group L) cows.</p

Using different RumiWatch noseband sensor and accelerometer (RumiWatch, ITIN+HOCH GmbH, Fütterungstechnik, Liestal, Switzerland) variable combinations as predictors of a cow being lame (numerical rating system according to Flower and Weary[38], NRS ≥ 2.5) in multivariable logistic regression and receiver operating characteristics analysis on different cutoff-values with corresponding sensitivity and specificity.

<p>Using different RumiWatch noseband sensor and accelerometer (RumiWatch, ITIN+HOCH GmbH, Fütterungstechnik, Liestal, Switzerland) variable combinations as predictors of a cow being lame (numerical rating system according to Flower and Weary[<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0155796#pone.0155796.ref038" target="_blank">38</a>], NRS ≥ 2.5) in multivariable logistic regression and receiver operating characteristics analysis on different cutoff-values with corresponding sensitivity and specificity.</p