A Deacetylation–Diazotation–Coupling Sequence: Palladium‐ Catalyzed CC Bond Formation with Acetanilides as Formal Leaving Groups

Abstract

Acetanilides can be deacetylated and diazotized in situ, and subsequently used in Pd-catalyzed coupling reactions without isolation of the diazonium intermediate. Heck reactions, Suzuki crosscoupling reactions, and a Pd-catalyzed [2 + 2 + 1] cycloaddition have been investigated as terminating C À C bond-forming steps of this one-flask sequence. The sequence does not require the exchange of solvents or removal of by-products between the individual steps, but proceeds by addition of reagents and catalysts in due course.

Hybrid Simulations of Solar Wind Proton Precipitation to the Surface of Mercury

“…In general, our model also shows a higher incidence rate to the southern hemisphere compared to the northern hemisphere (Figure 10d), which is associated with the northward offset in the planet's magnetic dipole. Furthermore, ground-based and MESSENGER observations both showed a north-south asymmetry in the antisunward Na tail with an excess in the northern tail (e.g., Baumgardner et al, 2008;McClintock et al, 2008;Potter & Killen, 2008;Vervack et al, 2010;Schmidt, 2013). Using a Monte Carlo simulation, Schmidt (2013) showed that the main source of Na in the northern tail is in fact the Na from the southern hemisphere that drifts to the opposite hemisphere of the tail as they are pushed antisunward by radiation pressure.…”

“…Because of the intense solar irradiation at Mercury's surface, which is due to the proximity of Mercury to the Sun, thermal and photon stimulated desorption are suggested to have the largest contribution to the formation of Mercury's neutral exosphere (e.g., Gamborino et al, 2019;Leblanc & Johnson, 2003;McGrath et al, 1986;Mura et al, 2009;Wurz et al, 2010). However, the particles released by these two processes have relatively low velocities and thus are more gravitationally bound to the planet, compared to the particles released by micrometeorite impact vaporization and solar wind ion sputtering (e.g., Leblanc & Johnson, 2003;Schmidt et al, 2010Schmidt et al, , 2012Schmidt, 2013;Wurz et al, 2010). The sputtering process depends on the momentum and energy of the impacting ions as well as the surface composition and sputtering yield (e.g., Killen et al, 2001;Lammer & Bauer, 1997;.…”

“…The high-latitude Na enhancements, which often appear at both hemispheres and are known as "two peaks" or "double peaks" (e.g., Mangano et al, 2015;Massetti et al, 2017;Orsini et al, 2018;Potter et al, 1999, are hypothesized to be related to the sputtering of neutral Na induced by the incidence of the solar wind plasma to the surface of Mercury through magnetospheric cusps (e.g., Killen et al, 2001;Killen et al, 2007;Leblanc & Johnson, 2003;Mangano et al, 2013Mangano et al, , 2015Massetti et al, 2007Massetti et al, , 2017. On the other hand, the dawn-dusk asymmetry is suggested to be related to the thermal and photon stimulated desorption processes that are more effective at dawn compared to dusk to knock off the neutrals from the surface (e.g., Mura et al, 2009;Potter et al, 2007), and the extended antisunward Na tail is due to the high solar radiation pressure (e.g., Baumgardner et al, 2008;Potter et al, 2002;Schmidt, 2013). Mangano et al (2015), using ground-based telescope observations, classified Na emission into two major recurrent patterns: a single peak at low latitudes close to the equator and the double peak at high latitudes.…”

“…Finally, we provide detailed analysis on plasma precipitation to the surface of Mercury under different solar wind plasma dynamic pressures and IMF orientations as well as the cusp dynamics and plasma precipitation through the cusps to explain some of the observed features in Na exosphere. Our global precipitation maps provide a better understanding of the magnetosphere-exosphere-surface coupling at Mercury (Milillo et al, 2005;Orsini et al, 2007) and can be applied in Monte Carlo simulations of Mercury's exosphere (e.g., Gamborino et al, 2019;Mura et al, 2009;Schmidt, 2013;, a tool that is required to better interpret observations by the European Space Agency (ESA)'s BepiColombo mission (Benkhoff et al, 2010;Milillo et al, 2010) and future ground-based telescope observations.…”

One Pot Asymmetric Synthesis of (R)‐Phenylglycinol from Racemic Styrene Oxide via Cascade Biocatalysis

“…As for (R)-phenylglycol oxidation, in order to recycle the expensive cofactor NAD + , an NAD + regeneration system employing AlaDH with NH 4 Cl as ammonia donor was introduced. [18] The conversion could reach as high as 99 % in glycine/NaOH buffer with pH ranging from 7.5-8.5 within 4 h, replacement of buffer constituent, higher pH or lower NH 4 Cl concentration significantly reduce the conversion (Table S3, supporting information). For transamination, L-Ala was utilized as the amino donor, since the by-product pyruvate can severely inhibit transaminase activity, [19] therefore, in situ removal of pyruvate is very critical not only for keeping the transaminase activity but also for pushing the reaction equilibrium.…”