STUDIES ON FORMATION OF REACTIVE SPECIES USING ORGANOMETALLIC COMPOUNDS OF GROUP 4B ELEMENTS AND THEIR APPLICATIONS TO ORGANIC SYNTHESIS

利用有机金属试剂合成其他方法难以合成的活性中间体已成为人们关注的焦点。我们表明，1，3-消除杂原子取代的有机硅化合物可以很容易地实现，非稳定的甲亚胺叶立德和硫代羰基叶立德，这是最重要的1，3-偶极子从合成和理论的观点是非常顺利地在温和的条件下得到。这构成了获得母体偶氮叶立德和硫代羰基叶立德的前所未有的有利途径。(1)不，不甲亚胺叶立德和硫代羰基叶立德的（甲硅烷基甲基）氨基甲基醚和氯甲基甲硅烷基甲基硫醚，分别容易制备，在缺电子烯烃、羰基化合物和N-杂芳族化合物存在下，通过刘易斯酸或氟化铯选择性地活化碳-氧键和碳-氯键，得到相应的吡咯烷、四氢噻吩、1，3-氧硫杂环戊烷和1，3-噻唑烷，产率相当高。(2)我们发现了2-二甲氨甲基-3-三甲基硅甲基-1，3-丁二烯作为2，2 ′-联烯丙基双自由基和2，2 ′-联烯丙基两性离子的方便制备和串联环加成反应。(3)五配位烯丙基硅酸酯及相关化合物，迄今未知，可以容易地制备和用作亲核试剂的高度化学选择性，区域选择性和立体选择性的还原和烯丙基化。

Much attention has been focused on the conventional generation of active synthetic intermediates using organometallic reagents which are hard to prepare by other method. We demonstrate that 1,3-elimination of -heteroatom substituted organosilicon compounds can be readily achieved and that non-stabilized azomethine ylides and thiocarbonyl ylide which are the most important 1,3-dipoles from both synthetic and theoretical points of view are obtained very smoothly under mild conditions. this constitutes an unprecedented and expedient route to parent azomthine ylide and thiocarbonyl ylide.(1) N-(Silylmethyl)aminomethyl ethers and chloromethyl silylmethyl sulfide as azomethine ylide and thiocarbonyl yilde synthous, respectively, readily prepared, undergo the activation of the carbon-oxygen and carbon-chlorine bond selectively by the Lewis acid or cesium fluoride in the presence of electron deficient alkenes, carbonyl compounds and N-heteroaromatics, to give the corresponding pyrrolidines, tetrahydrothiophenes, 1,3-oxathiolanes, and 1,3-thiazolidines in considerably high yield.(2) We found a convenient preparation and tandem cycloaddition reactions of 2-dimethylaminomethyl-3-trimethylsilylmethyl-1,3-butadiene that serves as 2,2'-biallyl diradical and 2,2'-biallyl zwitterion synthons.(3) Pentacoordinate allylsiliconates and related compounds, unknown hitherto, can be readily prepared and used as uncleophiles for the highly chemo-, regio- and stereo-selective reduction and allylation.