Novel Approaches to Stereo- and Enantioselective Syntheses of Versatile Intermediates via Unsaturated Organometallics of Main Group Metals

这笔续签拨款由有机合成计划提供资金。茨韦费尔博士正在继续他卓有成效的含有不饱和(碳-碳双键或三键)的有机金属试剂的开发。这些试剂有可能为一些害虫的一些信息素和海洋生物用来相互交流的一些化合物中的不寻常结构提供新的途径。本研究的具体目的是：(A)将1-甲氧基-1-烯-3-炔的乙炔基和烯醇醚基团精制成取代的五元环内酯、酰基硅烷、1，3-二炔和炔-1，2-丙二烯。它的特殊优点在于它有可能将廉价的起始原料转化为各种合成上有吸引力的衍生物；(B)开发1-(三甲基硅基)-1，3-二炔衍生的单-和双(锡基)烯的三个潜在的亲核中心，用于合成β-亚烷基-伽马-丁内酮和β，伽马-不饱和戊内酮。这些迄今尚不容易获得的系统的生物活性仍有待探索。我们将研究钯催化的锡基烯炔与亲电试剂的交叉偶联反应，以获得立体定义的共轭二烯、炔二烯和烯二炔，它们的结构特征存在于许多具有抗菌活性的真菌代谢物中；(C)手性3-冰片烯的制备及其作为模板的用途，用于在四碳中心和具有三个连续立体中心的化合物的合成中进行伴随绝对立体化学控制的非环立体控制。

This renewal grant is being funded by the Organic Synthesis Program. Dr. Zweifel is continuing his fruitful development of organometallic regents that contain unsaturation(carbon-carbon double or triple bonds). These reagents have the potential to provide new routes to the unusual structures found in some pheromones in some pests and in some compounds used by sea organisms to communicate with each other. The specific aims of the research are: (a) elaboration of the ethynyl and enol ether groups of 1-methoxybut-1-en-3-yne into substituted five- and six-membered ring lactones, acylsilanes, 1,3-diynes, and yne-1,2-propadienes. The special merit of this lies in its potential for transforming an inexpensive starting material into diverse and synthetically attractive derivatives; (b) exploitation of the three potentially nucleophilic centers of 1-(trimethylsilyl)-1,3-diyne derived mono- and bis(stannyl) enynes for syntheses of beta-alkylidene-gamma-butyrolactones and beta, gamma-unsaturated valerolactones. The biological activities of these hitherto not readily accessible systems remain to be explored. The palladium-catalyzed cross-coupling reactions of stannyl enynes with electrophiles will be investigated to gain access to stereodefined conjugated ene-dienes, yne-dienes, and ene-diynes whose structural features occur in many fungal metabolites, which possess antibiotic activity; (c) preparation of chiral 3-borolenes and investigation of their use as templates for effecting acyclic stereocontrol with concomitant control of absolute stereochemistry in syntheses of quaternary carbon centers and compounds having three consecutive stereogenic centers.