Cascade Reactions of Methyl 2-Chloro-2-cyclopropylideneacetate with Five- and Seven-Membered Cyclic Dienolates: A Novel Approach to the Bicyclo[4.2.1]nonane Segment of the Skeleton of Mediterraneols
Palladium-Catalyzed Asymmetric Direct Intermolecular Allylation of α-Aryl Cyclic Vinylogous Esters: Divergent Synthesis of (+)-Oxomaritidine and (−)-Mesembrine
enabling a straightforward enantioselectivesynthesis of 6-allyl-6-aryl-3-ethoxycyclohex-2-en-1-ones, common motifs embedded in numerous structurally diverse natural products. As an initial demonstration of the utility of this protocol, the first catalytic enantioselectivetotalsynthesis of (+)-oxomaritidine and an improved five-step catalytic enantioselectivesynthesis of (−)-mesembrine have been
The Cinchona Primary Amine-Catalyzed Asymmetric Epoxidation and Hydroperoxidation of α,β-Unsaturated Carbonyl Compounds with Hydrogen Peroxide
作者:Olga Lifchits、Manuel Mahlau、Corinna M. Reisinger、Anna Lee、Christophe Farès、Iakov Polyak、Gopinadhanpillai Gopakumar、Walter Thiel、Benjamin List
DOI:10.1021/ja402058v
日期:2013.5.1
Using cinchona alkaloid-derived primary amines as catalysts and aqueous hydrogenperoxide as the oxidant, we have developed highly enantioselective Weitz-Scheffer-type epoxidation and hydroperoxidation reactions of α,β-unsaturated carbonylcompounds (up to 99.5:0.5 er). In this article, we present our full studies on this family of reactions, employing acyclic enones, 5-15-membered cyclic enones, and
Synthesis of cyclopropyl silyl ethers and their facile ring opening by photoinduced electron transfer as key step in radical/radical cationic cascade reactions
作者:Prashant A. Waske、Jochen Mattay
DOI:10.1016/j.tet.2005.08.034
日期:2005.10
Various ring-fused cyclopropyl silyl ethers with an benzylic, olefinic or acetylenic side chain have been synthesized. Upon oxidative photoinducedelectrontransfer (PET) the cyclopropane ring opens and forms a reactive β-keto radical, which undergoes intramolecular cyclization. In some cases we observed only formation of ring opened non-cyclized products. With olefinic side chain 5-exo-trig mode of