Carbanion-accelerated Claisen rearrangements. 7. Phosphine oxide and phosphonate anion stabilizing groups
摘要:
The utility of phosphine oxide and phosphonate groups has been examined in the context of the carbanion-accelerated Claisen rearrangement (CACR). Both of the groups permit the construction of substituted allyl vinyl ethers by allyl oxide addition to phosphorus-substituted allenes. Extensive optimization was required to suppress isomerization of both the allenes and the vinyl ethers. Using potassium dimsylate and lithium chloride as the base, both the phosphine oxides and phosphonates rearranged readily at room temperature with complete regioselectivity in good yield (62-93%). The phosphonates also showed a high level of diastereoselectivity (92% de). The characteristic features of the CACR were compared with the original arylsulfone version.
An effective strategy for the preparation of (α,β-unsaturated hydrazones and pyrazole derivatives. Synthetic applications of β-functionalized phosphorus compounds.
作者:Francisco Palacios、Domitila Aparicio、Jesús M. de los Santos
DOI:10.1016/s0040-4020(01)89404-7
日期:1994.1
phosphonium salts 3 as web as β-hydrazano phosphine oxides 6 and phosphonates 7 are obtained from hydrazines, propargylphosphonium salts 2 and phosphorylated allenes 4 and 5. β-Functionalized compounds 3,6 and 7 are used for the synthesis of α,β-unsaturated hydrazones 1, pyrazoline 14 and pyrazole derivative 15.
Vinyl Azides Derived from Allenes: Thermolysis Leading to Multisubstituted 1,4-Pyrazines and Mn(III)-Catalyzed Photochemical Reaction Leading to Pyrroles
作者:K. V. Sajna、K. C. Kumara Swamy
DOI:10.1021/jo301694n
日期:2012.10.5
conditions furnished a new route for 1,4-pyrazines. A simple one-pot, Mn(III)-catalyzed photochemical route has been developed for multisubstituted pyrroles starting from allenes and 1,3-dicarbonyls via in situ-generated vinyl azides. The utility of new phosphorus-based pyrroles is also demonstrated in the Horner reaction. The structures of key products are unequivocally confirmed by X-ray crystallography
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.
Synthesis of secondary E-allylamines and β-aminophosphorylated compounds from β-functionalized enamines derived from phosphonium salts, phosphine oxides and phosphonates
作者:Francisco Palacios、Domitila Aparicio、Jesús García
DOI:10.1016/0040-4020(96)00498-x
日期:1996.7
A simple and stereoselective synthesis of secondary E-allylamines and from functionalized enamines derived from phosphine oxides , phosphonium salts and phosphonates is reported. Phosphorus compounds , and are obtained by amine addition to phosphorylated allenes , and phosphonium salts . Reduction of anamines and with hydrides leads to the formation of β-amino phosphine oxides and phosphonates . Allylamines
A simple strategy for the preparation of 4-aminoquinolines from β-functionalized enamines
作者:Francisco Palacios、Domitila Aparicio、Jesús García
DOI:10.1016/s0040-4020(97)10372-6
日期:1998.2
4-aminoquinolines substituted with a phosphine oxide group in the 3-position 1, is described. The key step is a heterocyclization of cyano-aryl β-enamino phosphine oxides 4. The treatment of β-enamines derived from phosphonium salts 7, with a base afforded phosphazenes 8 and the hydrolysis of these phosphazenes led to the formation of substituted 4-aminoquinolines 9.