In the past decade, there has been an increasing number of computational screening works to facilitate finding optimal materials for a variety of different applications. Unfortunately, most of these screening studies are limited to their initial set of materials and result in a brute-force type of screening approach. In this work, we present a systematic strategy that can find metal−organic frameworks (MOFs) with the desired properties from an extremely diverse and large set of over 100 trillion possible MOFs using machine learning and evolutionary algorithm. It is demonstrated that our algorithm can discover 964 MOFs with methane working capacity over 200 cm 3 cm −3 and 96 MOFs with methane working capacity over the current world record of 208 cm 3 cm −3 . We believe that this methodology can take advantage of the modular nature of MOFs and can readily be extended to other important applications as well.
Going to the source: Formamides or parent amines were used as an amino group source for the silver‐mediated amination of benzoxazoles. Although reactions with formamides proceeded at high temperatures, the direct amination with amines took place under much milder conditions (see scheme). Optically active amino groups could also be installed without racemization.
We describe a method for the site-selective construction of a
C(aryl)–C(sp3) bond by the palladium-catalyzed direct
allylation of arenes with allylic pivalates in the presence of AgOPiv to afford
the linear (E)-allylated arene with excellent regioselectivity;
this reaction occurs with arenes that have not undergone site-selective and
stereoselective direct allylation previously, such as monofluorobenzenes and
non-fluorinated arenes. Mechanistic studies indicate that AgOPiv ligated by a
phosphine reacts with the arene to form an arylsilver(I) species, presumably
through a concerted metalation–deprotonation pathway. The activated aryl
moiety is then transferred to an allylpalladium(II) intermediate formed by
oxidative addition of the allylic pivalate to the Pd(0) complex. Subsequent
reductive elimination furnishes the allyl–aryl coupled product. The
aforementioned proposed intermediates, including an arylsilver complex, have
been isolated, structurally characterized, and determined to be chemically and
kinetically competent to undergo the proposed elementary steps of the catalytic
cycle.
Because of the ubiquity of the secondary carbinol subunit, the development of new methods for its enantioselective synthesis remains an important ongoing challenge. In this report, we describe the first non-enzymatic method for the dynamic kinetic resolution (DKR) of secondary alcohols (specifically, aryl alkyl carbinols) through enantioselective acylation, and we substantially expand the scope of this approach, vis-à-vis enzymatic reactions. Simply combining an effective process for the kinetic resolution of alcohols with an active catalyst for the racemization of alcohols did not lead to DKR, due to the incompatibility of the ruthenium-based racemization catalyst with the acylating agent (Ac2O) used in the kinetic resolution. A mechanistic investigation revealed that the ruthenium catalyst is deactivated through the formation of a stable ruthenium-acetate complex; this deleterious pathway was circumvented through the appropriate choice of acylating agent (an acyl carbonate). Mechanistic studies of this new process point to reversible N-acylation of the nucleophilic catalyst, acyl transfer from the catalyst to the alcohol as the rate-determining step, and carbonate anion serving as the Brønsted base in that acyl-transfer step.
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