A regiospecific allyl–allylcoupling reaction between 1,3-dienes and allylboronates has been demonstrated under nickel catalysis. Salient features of this method include the earth-abundant metal catalyst, excellent regioselectivity and good functional group tolerance. Notably, even congested allyl substrates can also be applied to this protocol, thus allowing for the rapid preparation of a series of
Heck Reactions of Acrolein or Enones and Aryl Bromides – Synthesis of 3‐Aryl Propenals or Propenones and Consecutive Application in Multicomponent Pyrazole Syntheses
作者:Marvin Stephan、Jesco Panther、Fabio Wilbert、Pauline Ozog、Thomas J. J. Müller
DOI:10.1002/ejoc.202000066
日期:2020.4.16
The Heck reaction of (hetero)aryl bromides and acrolein or vinyl ketones using CataCXium® Ptb as a ligand, NaHCO3 as a base, and nBu4NCl provides an efficient access to 3‐(hetero)aryl propenals/propenones, which are directly employed in consecutive multicomponent syntheses of pyrazoles in a one‐pot fashion.
使用CataCXium®Ptb作为配体,NaHCO 3作为碱和n Bu 4 NCl进行(杂)芳基溴化物和丙烯醛或乙烯基酮的Heck反应,可以有效地获得3-(杂)芳基丙烯/丙烯酮。以单罐方式直接用于吡唑的连续多组分合成中。
Synthesis of 3,6-Dihydro-2<i>H</i>-1,2-oxazines via Dimethylsulfoxonium Methylide Addition to α,β-Unsaturated Nitrones
starting from α,β-unsaturatednitrones has been achieved. The nucleophilic addition of dimethylsulfoxonium methylide to the C═Nbond of an α,β-unsaturatednitrone to form an aziridine N-oxide followed by the Meisenheimer rearrangement affords 3,6-dihydro-2H-1,2-oxazine in up to 70% yield. Methylene was confirmed to be incorporated at the C3 position of the ring. A wide range of β-aryl-substituted α,β-unsaturated
从α,β-不饱和的硝酮开始,独特而有效地形成了3,6-二氢-2 H -1,2-恶嗪。二甲亚砜基亚甲基的亲核加成,形成一个α,β-不饱和硝酮的C═N键,形成氮丙啶N-氧化物,然后进行迈森海默重排,得到3,6-二氢-2 H -1,2-恶嗪产率70%。证实在环的C 3位置结合了亚甲基。广泛的β-芳基取代的α,β-不饱和硝酮可用于该反应。
Expanding the scope of the Babler–Dauben oxidation: 1,3-oxidative transposition of secondary allylic alcohols
作者:Patrick M. Killoran、Steven B. Rossington、James A. Wilkinson、John A. Hadfield
DOI:10.1016/j.tetlet.2016.07.076
日期:2016.8
We report the catalytic chromium-mediated oxidation of secondary allylicalcohols to give α,β-unsaturated aldehydes with exclusive (E)-stereoselectivity. This facile procedure employs catalytic PCC (5 mol %) and periodic acid (H5IO6) as a co-oxidant. This transformation occurs specifically with aromatic substituted allyl alcohols containing both electron withdrawing and electron donating substituents
Direct synthesis of 3-arylpropionic acids by tetraphosphine/palladium catalysed Heck reactions of aryl halides with acrolein ethylene acetal
作者:Mhamed Lemhadri、Henri Doucet、Maurice Santelli
DOI:10.1016/j.tet.2004.09.061
日期:2004.12
4-tetrakis(diphenylphosphinomethyl)cyclopentane as a catalyst, a range of aryl bromides undergoes Heck reaction with acrolein ethylene acetal. With this acetal, the selective formation of 3-arylpropionic acids/esters was observed. The functional group tolerance on the aryl halide is remarkable; substituents such as fluoro, methyl, methoxy, acetyl, formyl, benzoyl, nitro or nitrile are tolerated. Furthermore