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461.
Shenghan Teng Zhiwei Jiao Yonggui Robin Chi Jianrong Steve Zhou 《Angewandte Chemie (International ed. in English)》2020,59(6):2246-2250
Palladium‐catalyzed three‐component carboetherification of cyclic alkenes proceeded to give trans adducts exclusively with excellent enantioselectivity through a Wacker‐type pathway. The reaction is also applicable to other oxygen nucleophiles, such as water, phenols, and carboxylic acids, as well as some electron‐poor aryl amines. 相似文献
462.
Närhi K Franzén J Bäckvall JE 《Chemistry (Weinheim an der Bergstrasse, Germany)》2005,11(23):6937-6943
A novel palladium(0)-catalyzed cycloisomerization of enallenes has been developed. This reaction, catalyzed by [Pd(dba)2] (dba=dibenzylideneacetone) in acetic acid, results in the formation of cyclopentene derivatives and [n.3.0]bicyclic systems (n=3, 4) in good to high yields. The carbon-carbon bond-forming step is highly stereoselective to give cis-fused bicyclic systems. The presence of acetic acid as solvent and dba as ligand for palladium(0) turned out to be essential for the reaction in order to provide good reactivity and regioselectivity. 相似文献
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464.
Nina A. Nedolya Nataly I. Schlyakhtina Lyudmila V. Klyba Igor A. Ushakov Sergei V. Fedorov Lambert Brandsma 《Tetrahedron letters》2002,43(52):9679-9681
Reaction of lithiated methoxyallene, 1-ethoxyethoxyallene, 1-(methylthio)propyne and 2-butyne with methoxymethyl isothiocyanate, MeOCH2N=C=S followed by methylation affords the imidothioates H2C=C=C(R)C(SMe)=NCH2OMe [R=Me, OMe, OCH(Me)OEt, SMe]. Rearrangement to the fully conjugated systems H2C=CH---C(R)=C(SMe)---N=CHOMe and subsequent electrocyclisation of these compounds leads to the 5-substituted 6-(methylthio)-2-methoxy-2,3-dihydropyridines with good to excellent yields. In the presence of acidic catalysts or by heating at elevated temperatures these dihydropyridines eliminate methanol to afford 3-substituted 2-(methylthio)pyridines. The aroma compound 2-(methylthio)-3-pyridinol was obtained by acid-catalysed treatment of 3-(1-ethoxyethoxy)-2-(methylthio)pyridine. 相似文献
465.
Xiaobing Zhang Prof. Dr. Chunling Fu Prof. Yihua Yu Prof. Dr. Shengming Ma 《Chemistry (Weinheim an der Bergstrasse, Germany)》2012,18(42):13501-13509
A highly stereoselective iodolactonization of 4‐allenoic acids with a new sterically demanding electrophilic iodination reagent to afford optically active γ‐butyrolactones has been developed. The reaction shows high efficiency of axial chirality transfer and excellent Z/E selectivity and has been applied to the synthesis of chiral cis‐β,γ‐disubstituted γ‐butyrolactones to give very high diastereomeric and enantiomeric excess values. The reaction has been successfully utilized in the synthesis of naturally occurring compounds (+)‐cis‐whisky lactone and (+)‐cis‐3‐methyl‐4‐decanolide. 相似文献
466.
Dr. Xiao‐Feng Xia Yu‐Qi Wang Dr. Lu‐Lu Zhang Dr. Xian‐Rong Song Dr. Xue‐Yuan Liu Prof. Dr. Yong‐Min Liang 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(17):5087-5091
A new and efficient PdII‐catalyzed intermolecular annulation of N‐benzoylsulfonamide with allenes for the synthesis of 3,4‐dihydroisoquinolin‐1(2H)‐ones is reported. This C?H functionalization is compatible with ambient air and moisture, and it can be applied to terminal or internal allenes with di?erent synthetically attractive functional groups. Control experiments and a kinetic isotope effect study are conducted and a plausible mechanism is proposed. 相似文献
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468.
Metal Alkoxide Promoted Regio‐ and Stereoselective CO and CC Metathesis of Allenoates with Aldehydes 下载免费PDF全文
Minyan Wang Dr. Zhao Fang Prof. Dr. Chunling Fu Prof. Dr. Shengming Ma 《Angewandte Chemie (International ed. in English)》2014,53(12):3214-3217
The reaction of 2,3‐allenoates and aldehydes in the presence of an alkoxide affords alkyl 4,5‐diaryl‐3‐oxo‐2‐propylpent‐4(E)‐enoates and cis‐3,4‐diaryloxetanes through a formal C?O and C?C metathesis. A mechanism for this reaction has been proposed. 相似文献
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