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收率和容易分离的方式进行所需反应的试剂。为此，本实验室适当引入烯酮缩醛衍生物1作为烷氧羰基化、硅基化、硅基化、羧酸酐生成和硅基转移加成反应的试剂。在这项研究中，我们建立了由2,3- o-异丙基-d -甘油醛合成2-脱氧-d -核糖和由(2)-[(4s)-反式-2,2,5-三甲基-1,3-二氧基]亚甲基-[(1s)-1-苯乙基]胺- n-氧化物合成n-苯甲酰-1-丹诺胺的方法，利用邻硅基化酮缩醛的硅基转移加成反应（1a）。此外，我们还发现，在接近中性的条件下，用1a处理亚砜会引起pummer型重排。作为该反应的延伸，我们将该反应应用于< ω - >-氨基亚砜的新颖高效的分子内pummer型重排，从而高产出4至7元-硫内酰胺。一些具有< - >-烯烃取代基的亚砜的合成反应正在进一步研究中。

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.