Development of New Organosiiicon Reagents and Its Application to Environmentally Benign Organic Synthesis

1. 含二甲基硅基合成试剂的研制及其应用在碱或碱土金属盐的存在下，二甲基硅基烯醇化与醛的醛醇反应能有效进行。通过不同金属盐的反应，发现金属氯化物具有较高的活性，反应机理涉及到硅烯醇酯的亲核活化。有趣的是，即使在有水存在的情况下，醛醇反应仍在进行，甲醛的水溶液也是可用的。在氯化镁存在下，DMS烯醇酸酯与α-mopes反应，得到了高收率的Michael加合物。在相似的条件下，DMS烯化物也被添加到n -苯胺中。水与一定催化量的二异丙胺联合使用可有效诱导曼尼奇型反应。碱催化的mannich型反应具有高度的非对映选择性。碱或碱土金属盐能有效地促进α- dms酯与醛、酮的醛缩反应。与α-烯酮反应产生的醛醇加合物优先于迈克尔加合物。发现DMS醚和DMS胺在Lewis酸催化羰基化合物的还原醚化和胺化反应中是有效的2。在一定量的醋酸铟（III）存在下，烷基卤化物与苯基硅烷还原生成烷烃，收率高。这种还原是耐受极性官能团，如醚和酯基团。反应机理可能与醋酸铟（III）和苯基硅烷生成的氢化铟自由基还原有关。该还原体系适用于卤代烃与缺电子烯烃的分子间自由基加成反应

1. Development of Synthetic Reagents Bearing a Dimethylsilyl Group and Its ApplicationThe aldol reaction of dimethylsilyl (DMS) enolates with aldehydes proceeded efficiently in the presence of alkali or alkali earth metal salts. As the result of reactions using various metal salts, it was found that metal chlorides show high activity and the reaction mechanism involves nucleophilic activation of silyl enolates. Interestingly, the aldol reaction proceeded even in the presence of water, and an aqueous solution of formaldehyde was usable. In the presence of magnesium chloride, DMS enolates reacted with α-mopes to give Michael adducts in good to high yields. Under similar conditions, DMS enolates also added to N-tosylimines. The Mannich-type reaction was effectively induced by the combined use of water and a catalytic amount of diisopropylamine. The base-catalyzed Mannich-type reaction showed high levels of diastereoselectivity. The aldol reactions of α-DMS-esters with aldehydes and ketones were effectively accelerated by alkali or alkali earth metal salts. The reaction with α-enones afforded aldol adducts in preference to Michael adducts. DMS ethers and DMS amines were found to be effective in the Lewis acid-catalyzed reductive etherification and amination of carbonyl compounds2. Radical Reactions Using Indium Catalysts and HydrosilanesIn the presence of a catalytic amount of indium(III) acetate, alkyl halides underwent reduction with phenylsilane to give alkanes in good yield. This reduction is tolerant to polar functionalities such as ether and ester groups. The reaction mechanism probably involves radical reduction with indium hydride species generated from indium(III) acetate and phenylsilane. The reduction system was applicable to an efficient intermolecular radical addition of alkyl halides to electron-deficient alkenes