Palladium(II)-Catalyzed Regio- and Stereoselective Hydroarylation of Diphenylphosphorylallenes with Arylboronic Acids in the Presence of Sodium Hydroxide and Oxygen
The palladium(II)‐catalyzed hydroarylation of diphenylphosphorylallenes (via 1,2‐addition of the allenic double bond) with arylboronicacids in the presence of sodium hydroxide and oxygen is developed. The regioselectivities turn out to be well controlled, affording 2‐aryl‐3‐(diphenylphosphinyl)alkenes as the only product. Moreover, the stereoselectivities for reactions of γ‐substituted allenes can
An improved and effective method for the preparation of α,β-unsaturated oximes and isoxazole derivatives
作者:Francisco Palacios、Domitila Aparicio、Jesús M. de los Santos、Encina Rodríguez
DOI:10.1016/s0040-4020(97)10320-9
日期:1998.1
salts 10 are easily obtained by simple addition of hydroxylamine compounds 2 to substituted allenes 3 and 6 or to propargylphosphonium salt 9. These oximo derivatives are used for the synthesis of α,β-unsaturated oximes 1, and isoxazole derivatives 13.
Quinolinealkylphosphine oxides are obtained by thermal treatment of N-arylimines derivedfromphosphineoxides with N,N-dimethylformamide diethyl acetal (DMF-DEA). In a similar manner, quinolinealkylphosphonates are obtained by reaction of DMF-DEA with N-arylimines derivedfrom phosphonates or from their precursors, arylamines and carbonyl derivatives.
Studies on highly regio- and stereoselective fluorohydroxylation reaction of 3-aryl-1,2-allenyl phosphine oxides with Selectfluor
作者:Guangke He、Chunling Fu、Shengming Ma
DOI:10.1016/j.tet.2009.07.009
日期:2009.9
The fluorohydroxylation of allenyl phosphine oxides with Selectfluor in commercial MeCN without prior treatment or a mixed solvent of anhydrous MeCN (refluxed over CaH2 and distilled before use) and 7.0 equiv of H2O or MeNO2/H2O=10/1 afforded 2-fluoro-3-hydroxy-1(E)-alkenyl diphenyl phosphine oxides in moderate yields with very high regio- and stereoselectivities. The E-stereoselectivity is believed to be controlled by the phosphine oxide functionality. In the reaction of 3-(4-methoxyphenyl)-1,2-propadienyl diphenyl phosphine oxide, further fluorination on the electron-rich phenyl ring was also observed. (C) 2009 Elsevier Ltd. All rights reserved.