Synthesis, including asymmetric synthesis, of 1-substituted cyclopentenes from cyclobutanones with one-carbon ring-expansion by 1,2-carbon-carbon insertion of magnesium carbenoids
Treatment of 1-chlorovinyl p-tolyl sulfoxides, which were derivedfrom cyclobutanones and chloromethyl p-tolyl sulfoxide, with lithium enolate of tert-butyl carboxylates, amides, lithium α-sulfonyl carbanions, and lithium α-carbanion of acetonitrile gave adducts in high to quantitative yields. The adducts were treated with Grignard regents, such as i-PrMgCl and EtMgCl in toluene to afford 1-substituted
thermodynamically-stable isomers is negligible. On the other hand, the palladium-catalyzed sulfonylation of allylic acetates with sodium benzenesulfinate is accompanied by the isomerization to give the thermodynamically-controlled products selectively. These results can be explained by assuming that allylic nitro compounds are more reactive to the palladium catalyst than allylic acetates and sulfones.
Chelation-Induced Catalytic Multiple Arylation of Allylic 2-Pyridyl Sulfones
作者:Tomás Llamas、Ramón Gómez Arrayás、Juan Carlos Carretero
DOI:10.1002/adsc.200404180
日期:2004.12
metal-catalyzed protocol for the sequential multiarylation of cyclic allyl sulfones is described. The metal-coordinating ability of the 2-pyridyl group on the sulfone promotes the otherwise difficult intermolecular Heck monoarylation and diarylation of trisubstituted alkenes, as well as the copper-catalyzed allylicarylation with Grignard reagents.
Allylicnitrocompounds are directly converted into allylsulphides or allylsulphones with high regioselectivity on treatment with sodium benzenethiolate alone or with sodium benzenesulphinate in the presence of a catalytic amount of Pd(PPh3)4.
Regioselective synthesis of allylic sulfones by palladium-catalyzed denitro-sulfonylation of allylic nitro compounds
作者:Rui Tamura、Koji Hayashi、Masato Kakihana、Masanori Tsuji、Daihei Oda
DOI:10.1016/s0040-4039(00)61946-9
日期:1985.1
Allylicnitrocompounds undergo denitro-sulfonylation catalyzed by Pd(PPh3)4 or Pd(PPh3)4 +NaNO2 with PhSO2Na·2H2O to afford allylic sulfones regioselectively.