Direct synthesis of isoxazolidinylphosphines by cycloaddition of nitrones to diphenylphosphinoethenes and x-ray structure of 7,7-dimethyl-1-oxo-1-phenyl-3-diphenylphosphinyl-hexahydro-1H-pyrrolo [1,2-c] [1,3,2] oxazaphosphorine
摘要:
The 1,3-dipolar cycloaddition reaction of N-alkyl nitrones with diphenylvinylphosphines affords directly isoxazolidinylphosphines in satisfactory yields and in regio- and stereoselective manner. The parent diphenylvinylphosphine was found to favor the formation of 5-phosphinoisoxazolidines whereas diphenylpropenylphosphine gave instead the 4-phosphinoisoxazolidine regioisomer. However, in reactions utilizing an alkylarylvinylphosphine and/or N-arylnitrone, oxidation of the phosphine by the nitrone reagent was found to precede the cycloaddition. An attempted conversion of the bicyclic isoxazolidine derived from 2,2-dimethyl-dihydro-2H-pyrrole 1-oxide and diphenylvinylphosphine to the perhydropyrrolo[1,2-c] [1,3,2]oxaza-phosphorine ring system was accomplished through the use of the corresponding phosphine oxide derivative and provided a single diastereoisomer of the desired pyrrolooxazaphosphorinane characterized ultimately in the form of its dioxide hydrate by the X-ray diffraction technique.
进行了1-5的硝酮与二苯基乙烯基氧化膦(6)硫化物(7)和硒化物(8)的13-偶极环加成。除了亚砜33以外,还进行了将硝酮3作为模型与取代的乙烯基磷衍生物28-36的环加成反应,结果令人满意。核磁共振波谱(31 p 1 H和13C)可以对所有产品进行完全明确的区域化学鉴定和分配,以及它们的相对定量测定。基于1 H和13 C NMR数据,也将异恶唑烷立体中心的相对立体化学分配给化合物9-23和37-46。