working model suggests that the observed helicity of the porphyrin tweezer is dictated via steric differentiation experienced by the porphyrin ring bound to each chiral center. A variety of erythro and threo substrates were investigated to verify this chiroptical method. Their absoluteconfigurations were unequivocally determined, and thus a general mnemonic is provided for the assignment of chirality
报告了确定赤型和苏型二醇、氨基醇和二胺的绝对构型的通用且灵敏的非经验方案。通过增加金属卟啉的路易斯酸度,可以大大增强二醇与卟啉镊子系统的结合。在卟啉镊子主体和手性底物之间形成的超分子复合物表现出基于手性中心取代基的具有可预测符号的激子耦合双信号 CD 光谱。工作模型表明,观察到的卟啉镊子的螺旋度是通过与每个手性中心结合的卟啉环所经历的空间分化来决定的。研究了各种赤型和苏型底物以验证这种手性方法。他们的绝对配置是明确确定的,
Diastereoselectivity of the mercuration of acyclic allylic alcohols
作者:Bernd Giese、Dieter Bartmann
DOI:10.1016/s0040-4039(00)98432-6
日期:1985.1
The diastereoselectivity of the mercuration of acyclic alkenes can be reversed by changing the substituent in the allylic position; with alcohols the erythro isomers and with esters or hemiacetals the threo isomers and are formed predominantly (Table I).
The UV irradiation of aliphaticalcohols gave α-glycols as the principal products. The values of the dl-α-glycol ratios obtained in each example were analyzed.
Hydroxy-directed regio-diastereoselective ene reaction of singlet oxygen with chiral allylic alcohols
作者:Waldemar Adam、Bernd Nestler
DOI:10.1021/ja00065a013
日期:1993.6
The photooxygenation of chiral allylic alcohols 1a, (Z)-1f-k, ethers 1b-d, and acetate 1e gave the corresponding hydroperoxy homoallylic alcohols and derivatives 2 through the enereaction with singletoxygen. While the reaction of the acetate 1e proceeded erythro-diastereoselectively as a result of the classical cis effect, for the allylic alcohols 1a and (Z)-1f-k, in which an alkyl group is located
手性烯丙醇 1a、(Z)-1f-k、醚 1b-d 和乙酸酯 1e 的光氧化反应通过与单线态氧的烯反应得到相应的氢过氧高烯丙醇和衍生物 2。由于经典的顺式效应,乙酸酯 1e 的反应以赤型非对映选择性进行,对于烯丙醇 1a 和 (Z)-1f-k,其中烷基位于带羟基的取代基的顺式,高观察到threo选择性。这一发现可以通过立体中心的亲核羟基官能团与进入的亲电子单线态氧亲烯体的配位来解释
Stereoselective reduction of α-hydroxy ketones
作者:Tadashi Nakata、Tadasu Tanaka、Takeshi Oishi
DOI:10.1016/s0040-4039(00)87969-1
日期:1983.1
Reduction of α-hydroxy ketones with zinc horohydride afforded the -glycols in high stereoselectivity, while reduction of their α-(t-butyldiphenylsily)oxy derivatives with sodium bis(2-methoxyethoxy)aluminum hydride gave the isomeric . The structure-stereoselectivity relationship has been discussed.