与海洋素 A 和 B 具有相同立体化学但构象不同的模型螺胺的短而有效的合成是从 6-甲基四氢吡喃-2-one 分六或七步进行的。这些螺亚胺也通过还原烯醇醚仿生制备。从对山梨酸通过 11 个步骤制备了具有与海洋红素 A 相同立体化学和构象的更高取代度的螺亚胺。大环吡咯内酯通过 10 步立体定向制备。一个五步序列将内酯转化为晚期半亚胺醛中间体,该中间体能够抵抗甲基化和螺旋亚胺醛形成,从而产生海葵素 A。
Stereo-specific total synthesis of steroidal materials. 7-Substituted 3-oxo-1-heptenes or variants thereof are reacted with 2-alkylcycloalkane-1,3-diones yielding 3-substituted 6a .beta.-alkyl-cyclopenta [f] [1] benzopyrans or naphtho [2,1-b] pyrans. These are then subjected to a selective catalytic hydrogenation followed by an introduction of a hydroxy, alkoxy or acyloxy group at the 4a-position to produce a 3-substituted 6a .beta.,4a-hydroxy, alkoxy or acyloxy perhydrocyclopenta [f] [1] benzopyran or perhydro-naphtho [2,1-b] pyran. These latter compounds are then converted into 4- or 5-(3-oxoalkyl)perhydroindene-5-ones or perhydronaphthalene-6-ones which in turn can be converted to known steroidal materials by known methods.
Synthesis of the Spiroiminal Moiety of Marineosins A and B
作者:Xiao-Chuan Cai、Xiaoxing Wu、Barry B. Snider
DOI:10.1021/ol100333d
日期:2010.4.2
methylvalerolactone. Addition of vinylmagnesium bromide, protection of the alcohol, and reaction of the vinyl ketone with a protected pyrrole-2-carbonitrile N-oxide gave an isoxazoline. Hydrogenolysis of the N−O bond with Raneynickel gave a keto imine that cyclized to a hemi-iminal. O-Methylation, acid-catalyzed cleavage of the TES group and spiroiminal formation, and deprotection completed a seven-step synthesis
Lewis acid mediated nucleophilic substitution reactions of 2-alkoxy-3,4-dihydro-2H-1-benzopyrans: regiochemistry and utility in the synthesis of 3,4-dihydro-2H-1-benzopyran-2-carboxylic acids
作者:Noal Cohen、Beatrice Schaer、Gabriel Saucy、Rene Borer、Louis Todaro、Anne Marie Chiu
DOI:10.1021/jo00275a010
日期:1989.7
US3989724A
申请人:——
公开号:US3989724A
公开(公告)日:1976-11-02
Synthesis of the Spiroiminal Moiety and Approaches to the Synthesis of Marineosins A and B
作者:Xiao-Chuan Cai、Barry B. Snider
DOI:10.1021/jo402178r
日期:2013.12.6
A short and efficient synthesis of model spiroiminals that have the same stereochemistry as marineosins A and B, but different conformations, was carried out in six or seven steps from 6-methyltetrahydropyran-2-one. These spiroiminals were also prepared biomimetically by reduction of an enol ether. A more highly substituted spiroiminal with the same stereochemistry and conformation as marineosin A
与海洋素 A 和 B 具有相同立体化学但构象不同的模型螺胺的短而有效的合成是从 6-甲基四氢吡喃-2-one 分六或七步进行的。这些螺亚胺也通过还原烯醇醚仿生制备。从对山梨酸通过 11 个步骤制备了具有与海洋红素 A 相同立体化学和构象的更高取代度的螺亚胺。大环吡咯内酯通过 10 步立体定向制备。一个五步序列将内酯转化为晚期半亚胺醛中间体,该中间体能够抵抗甲基化和螺旋亚胺醛形成,从而产生海葵素 A。