Development of Acyl and Silyl Group Transfer Reactions of Ketene Acetal Derivatives and Their Applications to the Synthesis of Natural Products

在有机合成中，需要能够在中性或接近中性的条件下以高产率进行所需反应且易于分离的试剂。为了实现这一目的，我们从本实验室适当地引入了烯酮缩醛衍生物1作为烷氧基羰基化、甲硅烷基化、甲硅烯化、羧酸酐脱和甲硅烷基转移加成反应的试剂，并建立了从2，3-O-异亚丙基-D-甘油醛和从（2）-[（4s）-trans-2，2，5-三甲基-1，3-二氧戊环-4-基]亚甲基-[（1 s）-1-苯乙基]胺-N-氧化物，利用邻甲硅烷基化烯酮缩醛（1a）的甲硅烷基转移加成反应。此外，我们还发现，亚砜与1a的治疗引起Pummerer型重排在近中性条件下。作为该反应的延伸，我们将该反应应用于一种新的和有效的分子内Pummerer型重排的<omega>-酰胺亚砜，得到4至7元-硫代内酰胺在高产率。一些含烯取代基的亚砜的加成反应正在进一步<omega>研究中.

In organic synthesis, reagents are required which are able under neutral or nearly neutral conditions to bring about the desired reactions in high yields with easy isolation. For this purpose, ketene acetal derivatives 1 were suitably introduced as the reagents for alkoxycarbonylation, silylation, silylenation, carboxylic anhydride-formation, and the silyl group-transfer addition reactions from this laboratory.In connection with this study, we have established the synthesis of 2-deoxy-D-ribose from 2,3-O-isopropylidene-D-glyceraldehyde and N-benzoyl-1-daunosamine from (2)-[(4s)-trans-2,2,5-trimethyl-1,3-dioxolan-4-yl]methylene-[(1s)-1-phenylethyl]amine-N-oxide utilizing the silyl group-transfer addition reactions of o-silylated ketene acetal (1a). Furthermore, we have found that the treatment of sulfoxide with 1a caused a Pummerer-type rearrangement under nearly neutral conditions. As an extension of the reaction, we applied the reaction to a novel and efficient intramolecular Pummerer-type rearrangement of <omega>-amidosulfoxides which gave the 4 to 7-membered -thiolactams in high yields. Further studies on the annelation reactions of some sulfoxides haveing <omega>-olefinic substituents are in progress.