Cycloisomerization versus Hydration Reactions in Aqueous Media: A Au(III)-NHC Catalyst That Makes the Difference
摘要:
A novel water-soluble Au(III)-NHC complex has been synthesized and successfully applied in the intramolecular cyclization of gamma-alkynoic acids into enol-lactones under biphasic toluene/water conditions, thus representing a rare example of an active and selective catalyst for this transformation In aqueous media. Remarkably, competing alkyne hydration processes were not observed, even during the desymmetrization reaction of challenging 1,6-diyne substrates. In addition, after phase separation, the water-soluble Au(III) catalyst could be recycled 10 times without loss of activity or selectivity.
An Enantioselective Iodolactonization/Cross-Coupling Protocol for the Synthesis of Highly Substituted Enol Lactones
作者:Christoph Fricke、Michael Wilking、Constantin G. Daniliuc、Ulrich Hennecke
DOI:10.1002/ejoc.201800642
日期:2018.6.29
A sequence of catalytic enantioselectiveiodolactonization followed by Palladium‐catalyzed cross‐coupling provides rapid access to highly substituted enol lactones. With DHQD2PHAL as catalyst, moderate to very good enantioselectivities in the iodolactonization step can be obtained.
Thiophenol-Mediated Hydrogen Atom Abstraction: An Efficient Tin-Free Procedure for the Preparation of Cyclopentane Derivatives
作者:Florent Beaufils、Fabrice Dénès、Philippe Renaud
DOI:10.1021/ol049162g
日期:2004.7.1
[reaction: see text] An efficient procedure for running a cascade reaction involving 1,5-abstraction of a hydrogenatom followed by a radical cyclization is reported. Alkenyl radicals are generated from easily available terminal alkynes and thiophenol. This procedure eliminates the need of using the toxic tributyltin hydride and gives a greater amount of radical translocation products.
Ag(I)‐Catalyzed/Acid‐Mediated Cascade Cyclization of
<i>ortho</i>
‐Alkynylaryl‐1,3‐dicarbonyls to Access Arylnaphthalenelactones and Furanonaphthol Libraries via Aryl‐Disengagement
ortho-Alkynylaryl-1,3-dicarbonyl derivatives were utilized for the synthesis of arylnaphthalenelactone via cascadecyclization/decarboxylation in one-pot. These classes of compounds showed good potency in inhibiting protein-tyrosine phosphatase 1B (PTP1B) enzyme.