synthesis of functionalized alkyl aryl ketones is reported. Studies on the electronic and steric properties of mixed aryl anhydrides indicated that the cross-coupling favored with the electron-enriched aryl acyl group. DFT calculation on the oxidative addition of Pd(II) with 2,4,6-(Cl)3C6H2CO2C(O)Ph suggested that 2,4,6-(Cl)3C6H2C(O)–O bond cleavage was more kinetically disfavored than that of the PhC(O)–O
报道了钯/降冰片烯催化的邻位酰化,用于有效合成官能化的烷基芳基酮。对混合的芳基酸酐的电子和空间特性的研究表明,交叉偶联有利于富电子的芳基酰基。用2,4,6-(Cl)3 C 6 H 2 CO 2 C(O)Ph氧化Pd(II)的DFT计算表明2,4,6-(Cl)3 C 6 H 2 C (O)–O键的断裂在动力学上比PhC(O)–O键的断裂更不利于11.7 kJ / mol。
Total Synthesis of the Bacterial RNA Polymerase Inhibitor Ripostatin B
作者:Florian Glaus、Karl-Heinz Altmann
DOI:10.1002/anie.201200871
日期:2012.4.2
A modular and highly stereoselective synthesis of the title compound was developed. Key steps in the assembly of the carbon framework of ripostatinB (1; see scheme) were a stereoselective Paterson aldol reaction and a high‐yielding ring‐closing metathesis mediated by Grubbs first generation catalyst. The C15 hydroxy group was established through Tishchenko–Evans reduction in excellent yield and selectivity
A thermal O-to-C [1,3]-rearrangement of α-hydroxy acid derived enol ethers was achieved under mild conditions. The 2-aminothiophenol protection of carboxylic acids facilitates formation of the [1,3] precursor and its thermalrearrangement via stabilization of a radical intermediate. Experimental and theoretical evidence for dissociative radical pair formation, its captodative stability via aminothiophenol
作者:J.Edward Semple、Anne E. Guthrie、Madeleine M. Joullié
DOI:10.1016/s0040-4039(00)74551-5
日期:1980.1
A novel cyclization reaction is described which affords readily manipulable 3(2H)-dihydrofuranone ethylene ketals, useful in the total synthesis of an ascofuranone model, bullatenone, and muscarine analogs.
Enantioselective Conjunctive Cross-Coupling of Bis(alkenyl)borates: A General Synthesis of Chiral Allylboron Reagents
作者:Emma K. Edelstein、Sheila Namirembe、James P. Morken
DOI:10.1021/jacs.7b01774
日期:2017.4.12
conjunctive cross-coupling is used for the synthesis of enantioenriched allylboron reagents. This reaction employs nonsymmetric bis(alkenyl)borates as substrates and appears to occur by a mechanism that involves selective activation of the less substituted alkene followed by migration of the more substituted alkene during the course of a Pd-induced metalate rearrangement.