Mono- and Dialkylation of Derivatives of (1<i>R</i>, 2<i>S</i>)-2-Hydroxycyclopentanecarboxylic Acid and -cyclohexanecarboxylic acid<i>via</i>bicyclic dioxanones: Selective generation of three contiguous stereogenic centers on a cyclohexane ring
作者:Bernardo Herradón、Dieter Seebach
DOI:10.1002/hlca.19890720410
日期:1989.6.14
under kinetic control are shown to have cis-fused bicyclic structures. Oxidation of the seleno compounds 7–9 leads to α, β-unsaturated carbonyl derivatives 10–13 (Scheme 3) of which the products 12a–c with the CC bond in the carbocyclic ring (exocyclic on the dioxanone ring) are most readily isolated (70–80% from the saturated precursors). Michael addition of Cu(I)-containing reagents to 12a–c and subsequent
乙基(1 - [R,2小号(±)-2-羟基环戊烷和-环己烷羧酸1A和2A,分别地)在通过还原分别3-氧代环戊烷羧酸和环己烷,收率40和70%获得(方案2),与非发酵酵母,将其与甲醛,异丁醛和新戊醛转化为双环二恶烷酮衍生物3和4(方案3)。这些二恶烷的锂烯酸酯被烷基化(5a - 5i,5j,6a - 6g),羟烷基化(51,m,6d,e),酰化(5K,6C)和phenylselenenylated(7 - 9)配有通常高收率和优异的非对映选择性(方案3,表2和)。在动力学控制下形成的所有主要异构体均显示具有顺式稠合的双环结构。的硒的氧化化合物7-9导致α,β不饱和羰基衍生物10 - 13(方案3),该产品的12A - Ç与在碳环中的C-C键(环外的二氧杂环己酮环上的)是最容易地分离(70%至80%来自饱和前体)。含Cu(I)试剂的Michael加成12a – c和随后的烷基化反应生成带有反式环氧杂环丁烷环的二恶烷酮14a