[reaction: see text]. Beta-thioacetal-substituted aldehydes, which are conveniently prepared from the corresponding ynals, can be combined with a range of alkynes or electron-poor alkenes to deliver intermolecular hydroacylation adducts. The reactions employ [Rh(dppe)]ClO4 as a catalyst and are proposed to proceed via a chelated rhodium acyl intermediate. The thioacetal-containing products can be deprotected to the corresponding ketones or reduced to alkanes in good yields.
Download full-text PDF |
Source |
---|---|
http://dx.doi.org/10.1021/ol050638l | DOI Listing |
Chemistry
February 2013
Department of Chemistry, University of Oxford, Chemistry Research Laboratory, Mansfield Road, Oxford, OX1 3TA, UK.
A new functional-group tolerant, rhodium-catalyzed, sulfide-reduction process is combined with rhodium-catalyzed chelation-controlled hydroacylation reactions to give a traceless hydroacylation protocol. Aryl- and alkenyl aldehydes can be combined with both alkenes, alkynes and allenes to give traceless products in high yields. A preliminary mechanistic proposal is also presented.
View Article and Find Full Text PDFJ Am Chem Soc
December 2012
The Research Institute of Pharmaceutical Sciences, College of Pharmacy, Seoul National University, Seoul 151-742, Korea.
We report a completely substrate-controlled approach to the asymmetric total synthesis of representative dioxabicyclic bromoallene marine natural products with either a 2,10-dioxabicyclo[7.3.0]dodecene or 2,9-dioxabicyclo[6.
View Article and Find Full Text PDFOrg Biomol Chem
February 2008
Organic Pharmaceutical Chemistry, Department of Medicinal Chemistry, BMC, Uppsala, Box 574, SE-751 23, Sweden.
Highly stereoselective chelation-controlled Pd(0)-catalyzed beta-arylations and beta-vinylations of a five-membered chiral, pyrrolidine-based vinyl ether were achieved using aryl- and vinyl chlorides as substrates, yielding quaternary 2-aryl/vinyl-2-methyl cyclopentanones in 89-96% ee under neutral reaction conditions.
View Article and Find Full Text PDFJ Org Chem
July 2006
Department of Chemistry, University of Bath, Bath BA2 7AY, UK.
The use of beta-S-substituted aldehydes in rhodium-catalyzed intermolecular hydroacylation reactions is reported. Aldehydes substituted with either sulfide or thioacetal groups undergo efficient hydroacylation with a variety of electron-poor alkenes, such as enoates, in Stetter-like processes and with both electron-poor and neutral alkynes. In general, the reactions with electron-poor alkenes demonstrate good selectivity for the linear regioisomer, and the reactions with alkynes provide enone products with excellent selectivity for the E-isomers.
View Article and Find Full Text PDFJ Am Chem Soc
February 2006
Tri-Institutional Training Program in Chemical Biology, Pharmacology Program-Weill Graduate School of Medical Sciences of Cornell University, Memorial Sloan-Kettering Cancer Center, 1275 York Avenue, Box 422, New York, NY 10021, USA.
A Ti(Oi-Pr)4-mediated kinetic spiroketalization reaction has been developed for the stereocontrolled target- and diversity-oriented synthesis of spiroketals. In contrast to most existing methods for spiroketal synthesis, this reaction does not rely upon thermodynamic control over the stereochemical configuration at the anomeric carbon. Stereochemically diverse glycals are first alkylated at the C1-position to introduce a hydroxyl-bearing side chain, then epoxidized stereoselectively.
View Article and Find Full Text PDFEnter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!