Divergent gold-catalysed reactions of cyclopropenylmethyl sulfonamides with tethered heteroaromatics
作者:Melanie A. Drew、Sebastian Arndt、Christopher Richardson、Matthias Rudolph、A. Stephen K. Hashmi、Christopher J. T. Hyland
DOI:10.1039/c9cc06241f
日期:——
Cyclopropenylmethyl sulfonamides with tethered heteroaromatics have been demonstrated to undergo divergent gold-catalysed cyclisation reactions. A formal dearomative (4+3) cycloaddition takes place with furan-tethered substrates, yielding densely functionalised 5,7-fused heterocycles related to the bioactive curcusone natural products. Indole-tethered substrates display divergent reactivity giving
Carvone-Derived P-Stereogenic Phosphines: Design, Synthesis, and Use in Allene–Imine [3 + 2] Annulation
作者:Andrew J. Smaligo、Sriramurthy Vardhineedi、Ohyun Kwon
DOI:10.1021/acscatal.8b01081
日期:2018.6.1
[2.2.1] bicyclic chiral phosphines through straightforward syntheses starting from the natural product carvone. This design rationale prompted the development of an unforeseen C-dealkenylation reaction. We have applied these organocatalysts in the asymmetric syntheses of a bevy of pyrrolines, obtained in high yields and enantioselectivities, including a biologically active small molecule, efsevin.
Application of Photoclick Chemistry for the Synthesis of Pyrazoles via 1,3-Dipolar Cycloaddition between Alkynes and Nitrilimines Generated In Situ
作者:Richard Remy、Christian G. Bochet
DOI:10.1002/ejoc.201701225
日期:2018.1.23
The photolysis of tetrazoles leads to the extrusion of dinitrogen and forms a reactive nitrile imine intermediate. The latter can then react in situ with alkynes in a [3+2] cycloaddition providing pyrazoles. Some reactivity trends were identified, such as a preference for electron‐poor alkynes. On the tetrazole part, there is a clear preference for either aromatic or conjugated substituents.
Gold Catalysis: Non-Spirocyclic Intermediates in the Conversion of Furanynes by the Formal Insertion of an Alkyne into an Aryl-Alkyl CC Single Bond
作者:A. Stephen K. Hashmi、Tobias Häffner、Weibo Yang、Sreekumar Pankajakshan、Sascha Schäfer、Lara Schultes、Frank Rominger、Wolfgang Frey
DOI:10.1002/chem.201200306
日期:2012.8.20
It takes al‐kynes: The formation of furyl‐substituted heterocycles from furanynes with donor groups on the furan–alkyne tether and mechanistic control experiments indicate the involvement of open‐chained carbenium ions in the overall insertion of an alkyne into a CCbond, rather than the usual spirocyclic intermediates (see scheme).
作者:Silvio Carrettin、M. Carmen Blanco、Avelino Corma、A. Stephen K. Hashmi
DOI:10.1002/adsc.200606099
日期:2006.7
ω-alkynylfurans to phenols. Initial leaching of gold was observed, which could be minimised by calcining. Subsequent runs showed that once all soluble species had leached, the surface-bound, cationic gold species is still active and can reach turnover numbers of up to 391. This is the first time that a heterogeneous gold catalyst showed activity in the gold-catalysedphenolsynthesis.