A new approach towards synthesis of phosphorylated alkenes
摘要:
New method of synthesis of trans-vinylphosphonates via reaction of trimethylsilyl(methyl)phosphonites with carbonyl compounds in the presence of carbon tetrachloride has been developed. The reaction involves formation of C-trimethylsilyl substituted ylides and 2-chloro-1,2 lambda(5)-oxaphosphetanes as intermediates.
Rh(III)-Catalyzed Phosphine Oxide Migration Reactions: Selective Synthesis of 3-Phosphinoylindoles
作者:Chun-Hai Wang、Shang-Dong Yang
DOI:10.1002/asia.201800516
日期:2018.9.4
3‐Phosphinoylindoles are important components of biological active natural products and materials in pharmaceuticals. Herein, a new approach for the synthesis of 3‐phosphinoylindoles has been established by a Rh(III)‐catalyzed cyclization from readily accessible (2‐azidostyryl)diphenylphosphine oxides. This intramolecular transformation occurs through a unique phosphine oxide group migration and offers a straightforward
Heck Reactions Using Aryldiazonium Salts towards Phosphonic Derivatives
作者:Heiko Brunner、Nathalie Le Cousturier de Courcy、Jean-Pierre Genêt
DOI:10.1055/s-2000-6482
日期:2000.2
A facile synthesis of aryl vinylphosphonates has been based on Heck reaction of aryldiazonium salts bearing electrowithdrawing or donating groups with vinylphosphonates. A one-pot procedure consisting of Heck reaction and hydrogenation permits the clean formation of useful Wadsworth-Emmons reagents.
Interestingly, when using activatedaryl bromides the palladium loading could be lowered to only 0.25 mol%. While highlyactive when coupling aryl iodides (i.e. only 0.15 mol% required), the PdO/SiO2 catalyst was found to be inactive when considering aryl bromides. Deep study of this catalytic material revealed that in the case of aryl bromides, absence of in situ reduction of the catalyst precursor prevents
Pd-catalysed procedures for the direct Heck arylation of diethyl vinylphosphonate with various aryl or heteroaryl halides toward the synthesis of diethyl2-(aryl)vinylphosphonates are reported. Several homogeneous catalytic systems (i.e. Herrmann palladacycle, Nolan (NHC)-palladium catalyst, Pd(OAc)2/PPh3) were used and compared within the study. High conversions and selectivities were achieved under
报道了钯催化的乙烯基膦酸二乙酯与各种芳基或杂芳基卤化物直接进行Heck芳基化反应以合成2-(芳基)乙烯基膦酸二乙酯的方法。在研究中使用了几种均相催化体系(即,Herrmann palladacycle,Nolan(NHC)-钯催化剂,Pd(OAc)2 / PPh 3)。无论使用何种均相催化剂,在最佳条件下(2摩尔%[Pd],NMP,K 2 CO 3和140°C)都可以实现高转化率和选择性。