Resolution effect

In the Sharpless epoxidation of divinylmethanols only one of four possible stereoisomers is selectively formed. In this special case the diastereotopic face selectivity of the Shaipless reagent may result in diastereomeric by-products rather than the enantiomeric one, e.g., for the L -(-(-)-DIPT-catalyzed epoxidation of (E)-a-(l-propenyl)cyclohexaneraethanol to [S(S)-, [R(S)-, [S(R)- and [R(R)-trans]-arate constants is 971 19 6 4 (see above S.L. Schreiber, 1987). This effect may strongly enhance the e.e. in addition to the kinetic resolution effect mentioned above, which finally reduces further the amount of the enantiomer formed. 

Transfer hydrogenation is a mild and efficient means of reducing aldehydes, and can be advantageous over other reagents such as sodium borohydride. Clearly, the product is a primary alcohol and therefore not chiral, but a chiral center might be alpha to the aldehyde, in which case a resolution can be effected. Indeed, under the appropriate conditions the chiral center can be race-mized and a dynamic kinetic resolution effected [57]. 

While in the ideal case S(g) according to Eq. (57) clearly reflects the singular behavior at T due to substrate inhomogeneity and/or limited resolution the actual behavior of scattering data is quite smooth see Fig. 13b for an example. A detailed analysis of finite resolution effects on the structure factor of two-dimensional lattice gas models has been presented by Bartelt et af. If the... 

Resolution Effects with Peptides Undergoing Interconversion in Reversed-... 

Tension-resolution effects may also be in a negative direction. You fear failure so you withdraw. You dislike conflict so you avoid confrontation. 

Ketone mcthylenation can be coupled with concomitant optical resolution effected by chromatography by use of the related reagent 5. The adduct with a prochiral ketone has three asymmetric centers.2... 

As shown in Fig. 9, the spatial resolution effects high-resolution PEMFC imaging in two ways. The first effect is that the measured water profile will not contain discontinuous jumps or step-like image features, for instance at the boundary of the catalyst and microporous layer (MPL). Rather, an image of a step change will be described as an error function, with the width determined by as is demonstrated in Figure 9(a), where the transmission through a... 

This resolution is characterized by a bandwidth, b (which is as small as possible), and a clearance, s, between the respective bands (which is as large as possible). Both parameters are dependent upon the same influencing variables. The resolution effect is therefore defined as the quotient s/b and is taken as the target number of the process. 

Quite interestingly, the minor product 2-pheny 1-2,5-dihydrofuran (200) has the opposite configuration, i.e., (5)-200, compared to that of (/ )-199. However, this compound is produced with a significantly lower enantiomeric excess. It is possible that this is caused by a kinetic resolution effect in the alkene complex 205 the jr-bound hydridopalladium moiety in complex 205 could add again to the double bond. Base influence is also noteworthy, and the highest enantiomeric excess was achieved with l,8-bis(bisdimethylamino)naphthalene ( proton sponge ). 

DINSMS exactly incorporates resolution effects, multiple scattering and sample attenuation and is used in this paper to assess systematic errors introduced into cross section ratios, derived by fitting data with Eq. (20). 

With a Au filter, the energy resolution width is typically 1/4 that of the intrinsic peak width of H and D peaks and this introduces a 3% increase in the peak width due to resolution effects. With a U filter the resolution width is 1/10 that of the peak width and introduces a 0.5% increase in peak width. 

Substituted 3,4-dihydropyrimidines are inherently asymmetric. They are usually obtained as racemic mixtures. Enantiomerically pure and optically stable dihydropyrimidine-5-carboxylic acids (381) have been obtained by optical resolution effected by fractional crystallization of their diastereo-meric a-methylbenzylammonium salts. The absolute stereochemistry was established by x-ray analysis of diastereomeric a-methylbenzylammonium carboxylate. The enantiomeric acids (/ )-(381) and... 

Wang, C., and Barlow, R. S. "Spatial Resolution Effects on the Measurement of Scalar Variance and Scalar Gradient in Turbulent Nonpremixed Jet Flames." Experiments in Fluids 44 (2008) 633-45. 

Two independent tests designed to examine resolution effects on HASL predictivity have confirmed that the best results are achieved when HASL resolution lies within a 2-3 angstrom range. A more demanding test of HASL predictivity is in its application to an actual inhibitor set using an enzyme whose active site is well known. 

Angular resolution Effective area Field of Effective geom. 

Method Excitation detection Information chemical Information structural Monolayer resolution Effective probing depth Lateral resolution... 

Fig. 4. The measured total cross section for the 0.654 ev level in Ir. In this and the subsequent curves showing measured cross sections, both Doppler and possible resolution effects are present. From BNL-cslI. ...

McDermott, M.C., Stephenson, G.R., Hughes, D.L. and Walkington, A.J. (2006) Intramolecular asymmetric Heck reactions evidence for dynamic kinetic resolution effects. Org. Lett., 8, 2917-20. 

A typical example of a stepper is shown in Figure 5.4. Nikon Co. started selling the ArF immersion scanner NSR-S622D in February 2013. The ArF excimer lamp (193 nm) is equipped for a light source. This immersion system improved resolution effectively. A resolution of 38 nm is achieved by the scanner. The reduction ratio is 1 4. The NA of the system is 1.35. The maximum... 

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