我们报告了一种由钯催化,无碱,Suzuki-Miyaura偶联/异构化序列组成的顺序过程,用于合成1,3-二烯的简便方法。该序列将硼酸与炔丙醇偶合,在原位生成必需的丙二烯,然后通过加氢palpalation /脱氢palpalation过程将未活化的alene转化为其1,3-二烯。对于一系列硼酸,包括具有给电子和吸电子基团的硼酸,以及杂芳基硼酸,该方法是通用的。该过程的关键是无碱Suzuki-Miyauru偶联的硼酸副产物,该副产物可生成异构化所需的钯-氢络合物[H-Pd II -OB(OH)2 ]。
diastereo-, and enantioselective Diels–Alderreaction of β,γ-unsaturated α-ketoesters with (E)-1-phenyl dienes has been accomplished by using a stable and easily available chiral N,N′-dioxide/zinc(II) complex as catalyst. Only one isomer of the corresponding cyclohexenes with three chiral centers was obtained in good to excellent yields with excellent ee values under mild reaction conditions. The configurations
Transition metal-catalyzed dehydrogenation is a clean oxidation method requiring no additional oxidants. We have accomplished a heterogeneous Pd/C-catalyzed aqueous dehydrogenation of 1,4-cyclohexadienes and cyclohexenes to give the corresponding highly-functionalized arenes. Furthermore, various arenes could be efficiently constructed in a one-pot manner via a Diels–Alder reaction and the following
Aqueous Sodium Hydroxide Promoted Cross-Coupling Reactions of Alkenyltrialkoxysilanes under Ligand-Free Conditions
作者:Emilio Alacid、Carmen Nájera
DOI:10.1021/jo702570q
日期:2008.3.1
alkenyltrialkoxysilanes with aryl iodides, bromides, and chlorides are performed on water using sodium hydroxide as activator at 120 °C under normal or microwave heating. This process occurs in the presence of Pd(OAc)2 or 4-hydroxyacetophenone oxime-derived palladacycle 1 as precatalysts under ligand-free conditions with low Pd loadings (0.01−1 mol %) and using tetra-n-butylammonium bromide as additive. Different
Enantioselective Cyclobutenylation of Olefins Using <i>N</i>-Sulfonyl-1,2,3-Triazoles as Vicinal Dicarbene Equivalents
作者:Sajan C. Patel、Myles W. Smith、Jaron A. M. Mercer、Kensuke Suzuki、Noah Z. Burns
DOI:10.1021/acs.orglett.1c02331
日期:2021.8.20
enantioselective synthesis of cyclobutenes from olefins using N-sulfonyl-1,2,3-triazoles as vicinal dicarbene equivalents or alkyne [2 + 2] cycloaddition surrogates. Terminal and cis-olefins can be transformed into enantioenriched cyclopropanes via rhodium catalysis. Then, in one pot, treatment of these intermediates with tosyl hydrazide and base effects diazo formation followed by rhodium-catalyzed ring expansion
Gold-catalyzed isomerization of unactivated allenes into 1,3-dienes under ambient conditions
作者:Chun-Ming Ting、Yi-Ling Hsu、Rai-Shung Liu
DOI:10.1039/c2cc32131a
日期:——
We have developed a gold-catalyzed isomerization of unactivated allenes into 1,3-dienes with nitrosobenzene as an additive. This reaction proceeded almost exclusively at room temperature for highly substituted allenes. The utility of this reaction is manifested by the development of one-pot [4+2]-cycloaddition of allenes and reactive alkenes.