Selective Palladium-Catalyzed Allenic C−H Bond Oxidation for the Synthesis of [3]Dendralenes
作者:Youai Qiu、Daniels Posevins、Jan-E. Bäckvall
DOI:10.1002/anie.201706211
日期:2017.10.9
oxidation was developed, and it provides a novel and straightforward synthesis of [3]dendralene derivatives. A variety of [3]dendralenes with diverse substitution patterns are accessible with good efficiency and high stereoselectivity. The reaction tolerates a broad substrate scope containing various functional groups on the allene moiety, including ketone, aldehyde, ester, and phenyl groups. Also, a wide range
Regio- and Stereoselective Synthesis of Alkyl Allylic Ethers via Gold(I)-Catalyzed Intermolecular Hydroalkoxylation of Allenes with Alcohols
作者:Zhibin Zhang、Ross A. Widenhoefer
DOI:10.1021/ol800646h
日期:2008.5.1
carbene complex and AgOTf at roomtemperature for 1 h led to isolation of (E)-(3-phenethoxy-1-butenyl)benzene in 96% yield as a single regio- and stereoisomer. Gold(I)-catalyzed intermolecular allene hydroalkoxylation was effective for monosubsituted, 1,1- and 1,3-disubstituted, trisubstituted, and tetrasubstituted allenes and for a range of primary and secondary alcohols, methanol, phenol, and propionic
Intermolecular Hydroamination of Allenes with <i>N</i>-Unsubstituted Carbamates Catalyzed by a Gold(I) <i>N</i>-Heterocyclic Carbene Complex
作者:Robert E. Kinder、Zhibin Zhang、Ross A. Widenhoefer
DOI:10.1021/ol8010858
日期:2008.7.17
Reaction of 2,3-pentadienyl benzoate with benzyl carbamate catalyzed by a 1:1 mixture of (NHC)AuCl and AgOTf in dioxane at 23 degrees C for 5 h led to isolation of (E)-4-(benzyloxycarbonylamino)-2-pentenyl benzoate in 84% yield as a single regio- and diastereomer. Gold(I)-catalyzed hydroamination was effective for a number of N-unsubstituted carbamates and a range of substituted allenes.
Highly Regio- and Stereoselective Synthesis of 2(<i>E</i>),4-Alkadienoates via the Pd(0)-Catalyzed Reaction of Aryl Halides with 3,4-Alkadienoates
作者:Chunling Fu、Shengming Ma
DOI:10.1021/ol0473389
日期:2005.4.1
2(E),4-Alkadienoates were prepared highly stereoselectively via the Pd(O)/Ag2CO3-cocatalyzed reaction of 3,4-alkadienoates and aryl halides. The reaction is believed to proceed via the oxidative addition-carbopalladation-,beta-H elimination process. Compared to the other reported methods for the synthesis of 2,4-alkadienoates, in which usually only disubstituted C=C bonds were formed, the current reaction forms the trisubstituted or even tetrasubstituted C=C bond highly stereoselectively.
Highly Regio- and Stereoselective Cyclic Iodoetherification of 4,5-Alkadienols. An Efficient Preparation of 2-(1′(<i>Z</i>)-Iodoalkenyl)tetrahydrofurans
作者:Bo Lü、Xinpeng Jiang、Chunling Fu、Shengming Ma
DOI:10.1021/jo802079b
日期:2009.1.2
In this paper, an efficient way to synthesize 2-(1'(Z)-iodoalkenyl)tetrahydrofurans from 4,5-alkadienols and 12 was developed. The reaction of the 4,5-allenols with a substituent in the 3-position afforded the trans-2,3-disubstituted tetrahydrofurans with very high diastereoselectivity. However, when the axially optically active 4,5-allenol was treated with 12 in n-hexane, the efficiency for chirality transfer was low. This problem was circumvented by conducting the reaction in CH2Cl2 at room temperature and applying N-iodosuccinimide as the electrophilic reagent; however, the Z/E ratio for the products is much lower. Highly optically active Z-products may be prepared via the kinetic resolution via a Sonogashira coupling reaction with propargyl alcohol.