Alkene‐Directed
<i>N</i>
‐Attack Chemoselectivity in the Gold‐Catalyzed [2+2+1]‐Annulations of 1,6‐Enynes with
<i>N</i>
‐Hydroxyanilines
作者:Deepak B. Huple、Bhanudas D. Mokar、Rai‐Shung Liu
DOI:10.1002/anie.201507946
日期:2015.12
Kinetically unstable nitrones are generated from gold‐catalyzed reactions of 1,6‐enynes with N‐hydroxyanilines, and subsequently trapped by tethered alkenes to furnish [2+2+1]‐annulations. Our experimental data reveal that such nitrones arise from atypical N‐attackchemoselectivity that is triggered by tethered alkenes to facilitate the key protodeauration reaction.
A New Approach to Non-Coordinating Anions: Lewis Acid Enhancement of Porphyrin Metal Centers in a Zwitterionic Metal–Organic Framework
作者:Jacob A. Johnson、Brenna M. Petersen、Attila Kormos、Elena Echeverría、Yu-Sheng Chen、Jian Zhang
DOI:10.1021/jacs.6b05626
日期:2016.8.17
cationic metal center. We demonstrate the enhanced Lewis acidity of Mn(III)- and Fe(III)-porphyrins in the zwitterionic MOFs in three representative electrocyclization reactions: [2 + 1] cycloisomerization of enynes, [3 + 2] cycloaddition of aziridines and alkenes, and [4 + 2] hetero-Diels-Alder cycloaddition of aldehydes with dienes. This work paves a new way to design functional MOFs for tunable chemical
(Pentamethylcyclopentadienyl)Iridium Dichloride Dimer {[IrCp*Cl2]2}: A Novel Efficient Catalyst for the Cycloisomerizations of Homopropargylic Diols and N-Tethered Enynes
iridium dichloride dimer [IrCp*Cl2]2}-catalyzed hydroalkoxylation of bis-homopropargylicalcohols provides an efficient access to dioxabicyclo[2.2.1]ketals. The cycloisomerizations proceed under mild conditions, with low catalytic loadings and short reaction times. This new protocol involving an Ir(III) catalyst also promoted the cycloisomerization of nitrogen-tethered 1,6-enynes to give azabicyclo[4
Gold(I) complexes bearing P‐pyrrole phosphine ligands: Synthesis and catalytic activity towards cycloisomerization of 1,6‐enynes
作者:Elvia P. Sánchez‐Rodríguez、Salvador Cortés‐Mendoza、Jean‐Claude Daran、M. Carmen Ortega‐Alfaro、José G. López‐Cortés、Maryse Gouygou
DOI:10.1002/aoc.5709
日期:2020.8
P‐pyrrole phosphines (R2Ppyr), in which a pyrrole group is directly bonded to the phosphorus atom, act as monodentate k‐P ligands towards gold(I) center to afford either neutral or cationic mononuclear complexes as well as neutral dinuclear complexes. All of these new gold(I) complexes have been structurally characterized and their first uses in catalysis have demonstrated their effectiveness as precatalysts
Platinum-Catalyzed Cycloisomerization Reactions of Enynes
作者:Alois Fürstner、Frank Stelzer、Hauke Szillat
DOI:10.1021/ja0109343
日期:2001.12.1
PtCl(2) constitutes an efficient and practical catalyst for a set of different atom economical rearrangement reactions of enynes. This includes (i) a formal enyne metathesis reaction delivering 1,3-dienes, (ii) the formation of polycyclic vinylcyclopropane derivatives, and (iii) an unprecedented O-->C allyl shift reaction if unsaturated ethers are employed. Although these transformations produce significantly