CONSPECTUS: The catalytic activation and functionalization of unactivated C(sp(3))-H bonds of alkyl groups has undergone intense development in recent years. In particular, a variety of directing groups as well as native functional groups have been employed in combination with palladium(II) catalysis in order to perform a variety of intermolecular, and to some extent intramolecular reactions. In parallel, inspired by precedents in C(sp(2))-H arylation, our group and others have developed a different approach, which is the focus of this Account. This strategy relies on the use of oxidative addition of a carbon-leaving group bond to palladium(O) to induce intramolecular C(sp(3))-H activation and the subsequent formation of a C(sp(2))-C(sp(3)) or C(sp(3))-C(sp(3)) bond. Since our first publication in 2003, the construction of olefins and, more interestingly, of an array of valuable monocyclic and polycyclic systems has been reported according to this principle. (Hetero)aryl bromides were initially employed as reactants, but the scope was later expanded to include (hetero)aryl chlorides and triflates, alkenyl bromides, carbamoyl chlorides and alpha-chloroamides. Mechanistic studies enabled a better understanding of the C-H activation step, which was proposed to occur through ambiphilic metal-ligand activation-6 (AMLA-6), also known as concerted metalation deprotonation (CMD), and a better rationalization of the observed selectivity patterns. Moreover, the wealth of accumulated experimental data indicate that the number of atoms separating the C-H bond from Pd and the type of C-H bond are the main factors controlling the site-selectivity of the C-H bond cleavage. Recent efforts have been devoted to the development of enantioselective reactions. To this purpose, two different strategies have been employed: a chiral ancillary ligand in combination with an achiral base, and a chiral base in combination with an achiral ligand, and allowed for the achievement of high enantioselectivities in the construction of both tri- and tetrasubstituted stereocenters. On the other hand, the current C-H activation-based ring-forming method was applied to the synthesis of pharmacologically active substances and agrochemicals, as well as complex natural products such as the aeruginosins, thereby demonstrating its great potential for step-economical organic synthesis.
from #AlexandrosSfakianakis via Alexandros G.Sfakianakis on Inoreader http://ift.tt/2DbHEVz
via IFTTT
Εγγραφή σε:
Σχόλια ανάρτησης (Atom)
Δημοφιλείς αναρτήσεις
-
Publication date: Available online 4 January 2018 Source: European Journal of Radiology Author(s): Peiyao Zhang, Jing Wang, Qin Xu, Zhen...
-
Publication date: March 2017 Source: Free Radical Biology and Medicine, Volume 104 from #AlexandrosSfakianakis via Alexandros G.Sfak...
-
Dtsch med Wochenschr DOI: 10.1055/s-0043-100054 Hintergrund und Fragestellung Ein etablierter Weg, die optimale Behandlung von Tumorpatien...
-
Antibodies, Vol. 9, Pages 21: Construction of Ant... In Vivo and In Vitro Evaluation of Bull Semen Pro... Vertebral artery fenestration mimi...
-
Abstract Purpose F-18 fluorodeoxyglucose (FDG) positron emission tomography (PET) is emerging to be a useful tool in supporting the diag...
-
Does CBD Oil Lower Blood Pressure? This article was originally published at SundayScaries." Madeline Taylor POSTED ON January 13, 20...
-
Publication date: December 2017 Source: Advances in Biological Regulation, Volume 66 Author(s): Lauren Rusnak, Haian Fu The mitogen-activ...
-
Medicine by Alexandros G. Sfakianakis,Anapafseos 5 Agios Nikolaos 72100 Crete Greece,00302841026182, Butyric Acid from Probiotic Staphyloco...
-
Correction to: The IL-23p19/EBI3 heterodimeric cytokine termed IL-39 remains a theoretical cytokine in man The original article can be found...
Δεν υπάρχουν σχόλια:
Δημοσίευση σχολίου