CsF-Mediated in Situ Desilylation of TMS-Alkynes for Sonogashira Reaction
作者:Joseph S. Capani、John E. Cochran、Jianglin (Colin) Liang
DOI:10.1021/acs.joc.9b01307
日期:2019.7.19
A practical and mild set of conditions for the Sonogashirareaction utilizing CsF-mediated in situ TMS-alkyne desilylation followed by Sonogashira coupling has been developed for the synthesis of a variety of alkynyl benzenes and heteroarenes in good to excellent yields. This methodology demonstrates excellent functional group tolerance and simple purification, which allows large-scale industrial applications
Asymmetric α-Pentadienylation of Aldehydes with Cyclopropylacetylenes
作者:Min-Song Wu、Zhi-Yong Han、Liu-Zhu Gong
DOI:10.1021/acs.orglett.0c03466
日期:2021.2.5
cyclopropylacetylene and its derivatives as the pentadienylation reagent, an asymmetric regioselective asymmetric α-pentadienylation reaction of aldehydes is developed by cooperative catalysis of a chiral Pd(0) catalyst and a chiral Brønsted acid in the presence of a subschoichmetric amount of an achiral amine. α-Pentadienylated aldehydes are afforded with high yields and enantioselectivities as well as excellent
Gold-Catalyzed Oxidative Ring Expansions and Ring Cleavages of Alkynylcyclopropanes by Intermolecular Reactions Oxidized by Diphenylsulfoxide
作者:Chia-Wen Li、Kamalkishore Pati、Guan-You Lin、Shariar Md. Abu Sohel、Hsiao-Hua Hung、Rai-Shung Liu
DOI:10.1002/anie.201004647
日期:2010.12.17
A golden opportunity: A novel gold‐catalyzed oxidativering‐expansion of unactivated cyclopropylalkynes using Ph2SO has been developed (see scheme). For substrates bearing a donor group at the cyclopropane ring, preliminary results reveal a distinct cleavage of the cyclopropane unit; such a ringcleavage is further applicable to the synthesis of 2H‐pyrans. L=P(tBu)2(o‐biphenyl), Tf=triflate.
Ind2TiMe2-Catalyzed Addition of Methyl- and Ethylamine to Alkynes
作者:Klaudia Marcseková、Bernd Wegener、Sven Doye
DOI:10.1002/ejoc.200500458
日期:2005.11
simple hydrogenation-like experimental protocol for the addition of gaseous methyl- and ethylamine to alkynes in the presence of Ind2TiMe2 as the catalyst. For efficient hydroamination reactions it is sufficient to stir a mixture of the alkyne and the catalyst in toluene at temperatures between 80 °C (terminal alkynes) and 105 °C (internal alkynes) under a constant pressure of 1 atm of the corresponding
Silver-Catalyzed Tandem Cycloisomerization/[5 + 2] Cycloaddition of 3-Cyclopropylideneprop-2-en-1-ones with Oxidopyrylium Ylides to Form Bibridged Benzocycloheptanones
cycloisomerization/[5 + 2] cycloaddition reactions between readily accessible cyclopropyl-tethered allenyl ketones and benzopyranone-derived oxidopyrylium ylides. The reactions proceed via a cyclobutene-fused furan intermediate generated in situ by a cycloisomerization/1,2-carbene transfer/ring-expansion cascade. This method, which features an unprecedented formal [5 + 2] cycloaddition, delivers good to