A catalyst system comprising 10 mol % (Pd(OAc) and 20 mol % PPh3 effects the cyclisation of aryl halides onto proximate alkenes via 5-, 6-, and 7-exo-trig, and 7-endo-trig processes giving a variety of bridged-ring carbo- and hetero-cycles in excellent yield. Double bond isomerisation in the product is rarley encountered and may be suppressed by the addition of Tl(1) salts. One example of diastereospecific
Novel palladium catalysed two- and three-component thermal (conventional heating and microwave) cascade processes are described involving allenylation of an aryl iodide to generate a (π-allyl)palladium species, which are intercepted (inter- or intramolecularly) by a carbon or nitrogen nucleophile followed by intramolecular Michael addition to afford carbo- and heterocycles in good yields.
Palladium(II)‐Catalyzed Direct Access to Indeno[1,2‐
<i>c</i>
]isochromen‐5(11
<i>H</i>
)‐Ones via Intramolecular Oxypalladation‐Initiated Cascade Process
作者:Muthu Karuppasamy、B. S. Vachan、Tanvi Jandial、Sesuraj Babiola Annes、Nattamai Bhuvanesh、C. Uma Maheswari、Vellaisamy Sridharan
DOI:10.1002/adsc.202000456
日期:2020.7.16
A palladium(II)‐catalyzedcascade approach was established for the synthesis of indeno[1,2‐c ]isochromen‐5(11H )‐ones starting from 2‐alkynyl tert‐butyl benzoates bearing a pendant α,β‐unsaturated carbonyl moiety in high yields (up to 99%) under mild conditions. This strategy offered high atom and step economy by delivering isobutene as the only side product, and by generating two new bonds and two
建立了钯(II)催化的级联方法,用于合成带有[α,β-不饱和羰基]侧基的2-炔基叔丁基苯甲酸酯,从而合成茚并[1,2 - c ]异色素n-5(11 H)-酮。在温和的条件下以高收率(高达99%)收割。该策略通过提供异丁烯作为唯一的副产物,并在一次合成操作中生成两个新的键和两个环,从而提供了高原子和步进经济性。可以看到级联过程的机理,包括顺序的分子内氧合palpalpalation(6-endo-dig),分子内的烯烃插入和质子化步骤。