1595-03-5Relevant academic research and scientific papers
Relevance of Single-Transmetalated Resting States in Iron-Mediated Cross-Couplings: Unexpected Role of σ-Donating Additives
Rousseau, Lidie,Touati, Nadia,Binet, Laurent,Thuéry, Pierre,Lefèvre, Guillaume
, p. 7991 - 7997 (2021/05/26)
Control of the transmetalation degree of organoiron(II) species is a critical parameter in numerous Fe-catalyzed cross-couplings to ensure the success of the process. In this report, we however demonstrate that the selective formation of a monotransmetalated FeII species during the catalytic regime counterintuitively does not alone ensure an efficient suppression of the nucleophile homocoupling side reaction. It is conversely shown that a fine control of the transmetalation degree of the transient FeIII intermediates obtained after the activation of alkyl electrophiles by a single-electron transfer (SET), achievable using σ-donating additives, accounts for the selectivity of the cross-coupling pathway. This report shows for the first time that both coordination spheres of FeII resting states and FeIII short-lived intermediates must be efficiently tuned during the catalytic regime to ensure high coupling selectivities.
Iron-catalyzed alkylations of aryl sulfamates and carbamates
Silberstein, Amanda L.,Ramgren, Stephen D.,Garg, Neil K.
supporting information; experimental part, p. 3796 - 3799 (2012/08/28)
The alkylation of aryl sulfamates and carbamates using iron catalysis is reported. The method constructs sp2-sp3 carbon-carbon bonds and provides synthetically useful yields across a range of substrates (>35 examples). The directing group ability of sulfamates and carbamates, accompanied by their low reactivity toward conventional cross-couplings, renders these substrates useful for the synthesis of polyfunctionalized arenes.
Regioselective arene functionalization: Simple substitution of carboxylate by alkyl groups
Krueger, Tobias,Vorndran, Katja,Linker, Torsten
experimental part, p. 12082 - 12091 (2010/05/17)
Arenes with various alkyl side-chains were synthesized in high yields and excellent regioselectivities. Starting from toluic and naphthoic acids, the carboxylate group was conveniently substituted by alkyl halides by Birch reduction and subsequent decarbonylation. The method is characterized by inexpensive starting materials and reagents, and methylation of arenes was realized. Besides simple alkyl substituents, the scope of arene functionalization was extended by benzyl, fluoro, amino, and ester groups. We were able to control the alkylation of 1-naphthoic acid during Birch reduction by the addition of tert-butanol. This allowed the regioselective synthesis of mono and bis-substituted naphthalenes from the same starting material.
Gold-catalyzed synthesis of 1,3-disubstituted benzenes through tandem allylation/cyclization reaction of alkynals
Bhunia, Sabyasachi,Abu Sohel, Shariar Md.,Yang, Chao-Chin,Lush, Shie-Fu,Shen, Fwu-Ming,Liu, Rai-Shung
experimental part, p. 566 - 570 (2009/06/05)
Treatment of alkynals with 2-substituted allylsilanes and PPh3AuCl/AgOTf (5/3 mol%) catalyst led to formation of 1,3-disubstituted benzenes efficiently. This reaction sequence comprises an initial allylation of aldehyde, followed by cycloisomerization of enynes; PPh3AuOTf is active in both steps.
Integrated chemical process: One-pot aromatization of cyclic enones by the double elimination methodology
Orita, Akihiro,Yaruva, Jayamma,Otera, Junzo
, p. 2267 - 2270 (2007/10/03)
A variety of aromatic hydrocarbons bearing multiple alkyl substituents are accessible with perfect regiocontrol in a one-pot reaction starting from cyclo-hexenones and their aromatic analogues [Eq. (1)]. The present methodology can be further extended to the synthesis of polycyclic aromatic hydrocarbons. The drawbacks encountered in the Friedel-Crafts reaction are resolved since the reaction proceeds under basic conditions.
