132994-41-3Relevant articles and documents
Nucleophilic Addition to π-Allyl Gold(III) Complexes: Evidence for Direct and Undirect Paths
Rodriguez, Jessica,Holmsen, Marte Sofie Martinsen,García-Rodeja, Yago,Sosa Carrizo, E. Daiann,Lavedan, Pierre,Mallet-Ladeira, Sonia,Miqueu, Karinne,Bourissou, Didier
, p. 11568 - 11581 (2021)
π-Allyl complexes play a prominent role in organometallic chemistry and have attracted considerable attention, in particular the π-allyl Pd(II) complexes which are key intermediates in the Tsuji-Trost allylic substitution reaction. Despite the huge interest in π-complexes of gold, π-allyl Au(III) complexes were only authenticated very recently. Herein, we report the reactivity of (P,C)-cyclometalated Au(III) π-allyl complexes toward β-diketo enolates. Behind an apparently trivial outcome, i.e. the formation of the corresponding allylation products, meticulous NMR studies combined with DFT calculations revealed a complex and rich mechanistic picture. Nucleophilic attack can occur at the central and terminal positions of the π-allyl as well as the metal itself. All paths are observed and are actually competitive, whereas addition to the terminal positions largely prevails for Pd(II). Auracyclobutanes and π-alkene Au(I) complexes were authenticated spectroscopically and crystallographically, and Au(III) σ-allyl complexes were unambiguously characterized by multinuclear NMR spectroscopy. Nucleophilic additions to the central position of the π-allyl and to gold are reversible. Over time, the auracyclobutanes and the Au(III) σ-allyl complexes evolve into the π-alkene Au(I) complexes and release the C-allylation products. The relevance of auracyclobutanes in gold-mediated cyclopropanation was demonstrated by inducing C-C coupling with iodine. The molecular orbitals of the π-allyl Au(III) complexes were analyzed in-depth, and the reaction profiles for the addition of β-diketo enolates were thoroughly studied by DFT. Special attention was devoted to the regioselectivity of the nucleophilic attack, but C-C coupling to give the allylation products was also considered to give a complete picture of the reaction progress.
Electrochemical oxidative cyclization of olefinic carbonyls with diselenides
Guan, Zhipeng,Wang, Yunkun,Wang, Huamin,Huang, Yange,Wang, Siyuan,Tang, Hongding,Zhang, Heng,Lei, Aiwen
, p. 4976 - 4980 (2019/09/30)
The tandem cyclization of olefinic carbonyls with easily accessible diselenides facilitated by electrochemical oxidation has been successfully developed, which provides an environmentally friendly method for the construction of C-Se and C-O bonds simultaneously. A series of seleno dihydrofurans and seleno oxazolines, bearing fragile heterocycles, subtle C-I bonds and supernumerary vinyl groups, were forged using this elegant chelation strategy. Neither metal catalysts nor external chemical oxidants are required to promote this transformation.
Enantioselective cycloisomerization of 1,6-enynes to bicyclo[3.1.0]hexanes catalyzed by rhodium and benzoic acid
Masutomi, Koji,Noguchi, Keiichi,Tanaka, Ken
supporting information, p. 7627 - 7630 (2014/06/10)
It has been established that a cationic Rh(I)/(S)-Segphos or (S)-DTBM-Segphos complex and benzoic acid catalyze the enantioselective cycloisomerization of 1,6-enynes, possessing carbonyl groups at the enyne linkage, to 2-alkylidenebicyclo[3.1.0]hexanes. The present cycloisomerization may involve site selective γ-hydrogen elimination. The one-pot enantioselective cycloisomerization and lactonization of 1,6-enynes, leading to bicyclic lactones, has also been accomplished.
