Chiral Phosphoramide-Catalyzed Enantioselective Addition of Allylic Trichlorosilanes to Aldehydes. Preparative Studies with Bidentate Phosphorus-Based Amides
作者:Scott E. Denmark、Jiping Fu、Michael J. Lawler
DOI:10.1021/jo052203h
日期:2006.2.1
that more than one Lewis basic moiety (phosphoramide) is involved in the rate- and stereochemistry-determining step of enantioselectiveallylation, bidentate chiral phosphoramides were developed. Different chiral phosphoramide moieties were connected by tethers of methylene chains of varying length. The rate and enantioselectivity of allylation with allyltrichlorosilane promoted by the bidentate phosphoramides
Stereospecific Cross-Coupling Reactions of Aryl-Substituted Tetrahydrofurans, Tetrahydropyrans, and Lactones
作者:Emily J. Tollefson、David D. Dawson、Charlotte A. Osborne、Elizabeth R. Jarvo
DOI:10.1021/ja5076426
日期:2014.10.22
complex stereochemical arrays. Stereoselective synthesis of the cyclic template is utilized to control relative configuration; subsequent stereospecific nickel-catalyzed ring-opening affords the acyclic product. Aryl-substituted tetrahydrofurans and tetrahydropyrans undergo nickel-catalyzed Kumada-type coupling with a range of Grignard reagents to furnish acyclic alcohols with high diastereoselectivity
Bi(cyclopentyl)diol-Derived Boronates in Highly Enantioselective Chiral Phosphoric Acid-Catalyzed Allylation, Propargylation, and Crotylation of Aldehydes
作者:Jinping Yuan、Pankaj Jain、Jon C. Antilla
DOI:10.1021/acs.joc.0c01646
日期:2020.10.16
catalytic addition of bi(cyclopentyl)diol-derived boronates to aldehydes promoted by chiralphosphoricacids, allowing for the formation of enantioenriched homoallylic, propargylic, and crotylic alcohols (up to >99% enantiomeric excess (ee), diastereomeric ratio (dr) >20:1). These boronate substrates provided superior enantioselectivities, allowing for the reactions to proceed with low catalyst loading
We report here a Ni-catalyzed reductive coupling of aldehydes with widely available 1,3-dienes under visible-light photoredox dualcatalysis. The homoallyic alcohols are obtained in broad scope with complete branched regioselectivity. Hantzsch ester is used as the hydrogen radical source to oxidize low-valent nickel salt affording Ni–H species. Preliminary mechanistic studies indicate a successive
Kinetic Diastereoselection of Homoallylic Indium Alkoxides: <i>Syn</i> Crotylation of Arylaldehydes
作者:Guy C. Lloyd-Jones、Tim Russell
DOI:10.1055/s-1998-1804
日期:1998.8
Reaction of crotylindium sesquibromide with benzaldehyde in DMF at 20 °C affords syn-1-phenyl-2-methylbut-3-enol (ca. 40% de) after aqueous acidic work-up. At 22 °C in DMF, prior to work-up a greater relative proportion of the anti intermediate is decomposed as compared to its syn diastereomer. The resultant kinetic diastereoselection upgrades, the syn/anti ratio to 99/1 with a concomitant drop in overall yield.