55 research outputs found
Overturning established chemoselectivities : selective reduction of arenes over malonates and cyanoacetates by photoactivated organic electron donors
The prevalence of metal-based reducing reagents, including metals, metal complexes, and metal salts, has produced an empirical order of reactivity that governs our approach to chemical synthesis. However, this reactivity may be influenced by stabilization of transition states, intermediates, and products through substrate-metal bonding. This article reports that in the absence of such stabilizing interactions, established chemoselectivities can be overthrown. Thus, photoactivation of the recently developed neutral organic superelectron donor 5 selectively reduces alkyl-substituted benzene rings in the presence of activated esters and nitriles, in direct contrast to metal-based reductions, opening a new perspective on reactivity. The altered outcomes arising from the organic electron donors are attributed to selective interactions between the neutral organic donors and the arene rings of the substrates
Diagnosis for ecological intensification of maize-based smallholder farming systems in the Costa Chica, Mexico
Pädagogische Auslandsstudien im Dienste der auswärtigen Politik : ein Ergänzungsvorschlag zur Auslandsdenkschrift
The Box Plot Experiment in Grossbeeren after six rotations: Effect of fertilization on crop yield
Conjugate addition of mixed diorganozinc compounds and functionalized organozinc cuprates to nitroolefins
Rimkus A, Sewald N. Conjugate addition of mixed diorganozinc compounds and functionalized organozinc cuprates to nitroolefins. Organic Letters. 2002;4(19):3289-3291.The copper-catalyzed conjugate addition of symmetrical and mixed diorganozinc compounds as well as functionalized diorganozinc cuprates to nitroolefins leads to synthetically versatile nitro compounds in moderate to good yields. Mixed TMSM-organozinc compounds are suitable reagents for conjugate addition, since the TMSM group is not being transferred. Ipso substitution is observed in the absence of a catalytic amount of copper(I) salt. The nitroalkene moiety in 3-nitroacrylates proved to be the predominant Michael acceptor
Kinetics Of The Interaction Of Bovine Pancreatic Trypsin Inhibitor (Kunitz) With α-Chymotrypsin
The structure of the complex formed by bovine trypsin and bovine pancreatic trypsin inhibitor
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