在室温下可见光照射下,核黄素四乙酸酯有效地催化了脂肪族羧酸与芳基苯乙烯基砜的脱羧烯基化反应。这种无金属方案具有成本效益、环境友好,并为相应的烯烃提供出色的 ( E )-非对映控制。该方法还可用于通过使用炔基砜作为自由基受体来区域选择性地制备内部炔烃。通过进行 ( E ) 到 ( Z ) 光异构化、铁催化的由 2-苯氧基羧酸底物衍生的苯氧基的烯丙基取代,以及合成-环氧化和非对映选择性分子内碘芳基化。基于对照实验和 DFT 计算,我们提出了一种反应机制,可以解释观察到的区域选择性和非对映选择性。
Practical Iron-Catalyzed Allylations of Aryl Grignard Reagents
作者:Matthias Mayer、Waldemar M. Czaplik、Axel Jacobi von Wangelin
DOI:10.1002/adsc.201000228
日期:2010.9.10
reaction between aryl halides and allyl electrophiles has been developed. The underlying domino process exhibits high versatility with respect to the allylic leaving group (acetate, tosylate, diethyl phosphate, methyl carbonate, trimethylsilanolate, methanethiolate, chloride, bromide) and high economic and environmental sustainability with respect to the catalyst system (0.2–5 mol% tris(acetylacetonato)iron(III)
A Highly Active and Reusable Self-Assembled Poly(Imidazole/Palladium) Catalyst: Allylic Arylation/Alkenylation
作者:Shaheen M. Sarkar、Yasuhiro Uozumi、Yoichi M. A. Yamada
DOI:10.1002/anie.201103799
日期:2011.9.26
Gobs of globules: A polymeric imidazole/acrylamide palladiumcatalyst, MPPI‐Pd (M=PdIICl and Pd0), was utilized for the allylicarylation/alkenylation of allylic esters with aryl/alkenylboronic acids and tetraaryl borates. Low catalyst loadings efficiently promoted the reaction with a catalytic turnover number of 20 000–1 250 000. The catalyst can be reused without loss of catalytic activity.
小球小滴:聚合的咪唑/丙烯酰胺钯催化剂MPPI-Pd(M = Pd II Cl和Pd 0)用于芳基/烯基硼酸和四芳基硼酸酯的烯丙基酯的烯丙基芳基化/烯基化反应。较低的催化剂载量有效地促进了反应,催化转化数为20000-1250000。可以重复使用催化剂而不会损失催化活性。
Self-Assembled Poly(imidazole-palladium): Highly Active, Reusable Catalyst at Parts per Million to Parts per Billion Levels
作者:Yoichi M. A. Yamada、Shaheen M. Sarkar、Yasuhiro Uozumi
DOI:10.1021/ja210772v
日期:2012.2.15
uniformly dispersed in MEPI-Pd. MEPI-Pd was utilized for the allylic arylation/alkenylation/vinylation of allylic esters and carbonates with aryl/alkenylboronic acids, vinylboronicacid esters, and tetraaryl borates. Even 0.8-40 mol ppm Pd of MEPI-Pd efficiently promoted allylic arylation/alkenylation/vinylation in alcohol and/or water with a catalytic turnover number (TON) of 20,000-1,250,000. Furthermore
A cross-coupling reaction between aryl- and vinylboronicacids and various allylic bromides proceeded without the use of a transition-metal catalyst to give the corresponding allylated products in moderate to good yields. The use of an inorganic base (KF or Cs2CO3) and a small amount of water is crucial in obtaining good performance in the present transition-metal-free reaction. transition-metal-free
在不使用过渡金属催化剂的情况下,进行了芳基和乙烯基硼酸与各种烯丙基溴之间的交叉偶联反应,以中等至良好的产率得到了相应的烯丙基化产物。在目前的无过渡金属反应中,使用无机碱(KF或Cs 2 CO 3)和少量水对于获得良好的性能至关重要。 无过渡金属-CC键形成-芳基和乙烯基硼酸
Direct alkylation of aromatics using alcohols in the presence of NaHSO4/SiO2
Simple and efficient procedure for alkylation of aromatics from alcohols in the presence of NaHSO4/SiO2 was developed. Various triaryl methanes were obtained in good yields in short reaction time. For instance the reaction of mesitylene with benzhydrol in the presence of NaHSO4/SiO2 gave the corresponding triaryl methane in a quantitative yield. NaHSO4/SiO2 was regenerated by simple treatment and could