Palladium-Catalyzed Alkoxycarbonylation of (Z)-2-En-4-yn Carbonates Leading to 2,3,5-Trienoates
摘要:
Pd(0)-catalyzed carbonylation of (Z)-2-en-4-yn carbonates in the presence of a balloon pressure of CO in an alcohol donates vinylallenyl esters with an exclusively E-configuration and in high yields. The fact that no such reactivity could be observed with E-configured enyne carbonates may indicate that the reaction is promoted via the cooperative coordination of palladium with both alkynyl and carbonate moieties.
α-(<i>N</i>-Carbamoyl)alkylcuprate Chemistry in the Synthesis of Nitrogen Heterocycles
作者:R. Karl Dieter、Kai Lu
DOI:10.1021/jo016053w
日期:2002.2.1
beta-ynoates, alpha-allenyl esters, or alpha.beta-enoates or enimides undergo N-Boc deprotection and cyclization onto the ester functionality upon treatment with PhOH/TMSCl, catecholboron bromide, or trimethylsilyl triflate. This two-pot sequence provides synthetic routes to 4-alkylidinepyrrolidine-2-ones, 4-alkylidinepyrrolizidin-2-ones, and 4-alkylidineindolizidin-2-ones via allenylesters; pyrrolin-2-ones
Ligand Effects on the Pd-Catalyzed Cross-Coupling Reaction of 3-Iodoalk-2-enoates with Propargyl/1,2-Allenylic Metallic Species: An Efficient Regiodivergent Synthesis of 2,4,5-Trienoates
作者:Jinbo Zhao、Yihua Yu、Shengming Ma
DOI:10.1002/chem.200901287
日期:2010.1.4
makes a big difference: The 1,3‐lithiumshift of propargyl/1,2‐allenyl lithium has been tuned and applied in a subsequenttransmetalation and Pd‐catalyzed Negishi couplingreaction with 3‐iodoalk‐2‐enoates to give a highly regioselective and regiodivergent synthesis of 2,4,5‐trienoates. It was discovered that ligands play a very important role in the cross‐couplingreactions with respect to both regioselectivity
Lead Tetraacetate Induced Addition Reaction of Difluorodiiodomethane to Alkenes and Alkynes. Synthesis of Fluorinated Telechelic Compounds
作者:An-Rong Li、Qing-Yun Chen
DOI:10.1055/s-1997-1378
日期:1997.12
Lead tetraacetate (LTA) can smoothly induce the addition reaction of difluorodiiodomethane (1) with electron-rich alkenes at 60°C in diglyme to give monoadducts (RCHICH2CF2I) and diadducts (RCHICH2)2. The similar, clean reaction of fluoroolefins, such as tetrafluoroethene, hexafluoropropene, with 1 occurs only in acetic acid. However, non-fluorinated β-iodo-α,β-unsaturated carboxylic esters are obtained when 1 reacts with alkynes in alcohol. The iododifluoromethyl radical generated by possible pathways from 1 with LTA is discussed.
Pd(0)-catalyzed carbonylation of (Z)-2-en-4-yn carbonates in the presence of a balloon pressure of CO in an alcohol donates vinylallenyl esters with an exclusively E-configuration and in high yields. The fact that no such reactivity could be observed with E-configured enyne carbonates may indicate that the reaction is promoted via the cooperative coordination of palladium with both alkynyl and carbonate moieties.