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Efficient Synthesis of the alkyl chains with multiple stereogenic centers

具有多个立体中心的烷基链的高效合成

基本信息

批准号：
21655035
负责人：
HOSOKAWA Seijiro
金额：
$ 2.22万
依托单位：
Waseda University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Challenging Exploratory Research
财政年份：
2009
资助国家：
日本
起止时间：
2009 至 2011
项目状态：
已结题

项目摘要

Two subjects shown below have been successfully performed.(1) Development of remote asymmetric induction methodologies by using chiral vinylketene N, O-acetalsThe chiral vinylketene N, O-acetal, derived from α-methyl-α,β-unsaturated imide, was found to give syn adduct stereoselectively by the Lewis-acid mediated aldol reaction with acetals. The same N, O-acetal also gave syn adducts by reaction with aldehyde and excess amount of TiCl_4. This N, O-acetal has already known to afford anti adducts stereoselectively by reacting with aldehyde and one equivalent of TiCl_4.Therefore, we established stereo-divergent synthesis ofδ-alkoxy-γ-methyl-α,β-unsaturated imide by choosing amount of TiCl_4.The chiral vinylketene N, O-acetal has reacted with acid anhydrides to proceed acylation, the 1, 6-asymmetric induction reaction. Additionally, the chiral vinylketene N, O-acetal without the α-methyl group also performed the remote asymmetric induction.(2) Synthesis of polyketide haing multiple stereogenic centersThe adducts of the remote asymmetric induction reaction mentioned above have been submitted to the regio-and stereoselevtive reduction to give methyl-branched fatty acids with desired stereochemistry.The adduct of the chiral vinylketene N, O-acetal and an α-methyl-α,β-unsaturated aldehyde has both allylic alcohol and the α,β-unsaturated imide. Taking advantage of the adduct, we have realized the regio-and stereoselective reduction and established the short step synthesis of reducted polyketide chains.

已成功实施了以下两个受试者。(1)以α-甲基-α，β-不饱和酰亚胺为原料合成的手性乙烯基烯酮N，O-缩醛，通过Lewis酸催化的Aldol反应，可立体选择性地与缩醛反应生成顺式加成物。同样的N，O-缩醛也可与醛和过量的TiCl_4反应生成顺式加合物。已知该N，O-缩醛与醛和1当量的TiCl_4反应可立体选择性地生成反加成物，因此，我们通过选择TiCl_4的用量，建立了δ-烷氧基-γ-甲基-α，β-不饱和酰亚胺的立体发散合成方法。此外，不含α-甲基的手性乙烯基烯酮N，O-缩醛也进行了远程不对称诱导。(2)具有多个立体异构中心的聚酮化合物的合成将上述不对称诱导反应的加成物进行区域选择性还原和立体选择性还原，得到了具有所需立体化学结构的甲基支链脂肪酸，手性乙烯基烯酮N，O-缩醛与α-甲基-α，β-不饱和醛的加成物既含有烯丙醇，又含有α，β-不饱和酰亚胺。利用该加成物，实现了区域和立体选择性还原，建立了还原聚酮链的一步合成方法。