This invention discloses new compounds of the formula ##STR1## wherein R.sup.1 is selected from the group consisting of hydrogen and alkyl; X is halogen; R.sup.2 is selected from the group consisting of alkyl, alkenyl and alkynyl; n is the integer 1 or 2; and R.sup.3, R.sup.4, R.sup.5 and R.sup.6 are each selected from the group consisting of hydrogen and alkyl. Further disclosed are herbicidal compositions utilizing the aforedescribed compounds.
Acid-Catalyzed Transacetalization from Glycol to Pinacol Acetals
作者:Yvonne Seeleib、Gregor Nemecek、Dominik Pfaff、Bastian D. Süveges、Joachim Podlech
DOI:10.1080/00397911.2014.912330
日期:2014.10.18
transacetalization of glycolacetals, frequently used as protecting groups of the aldehyde function, into the more stable pinacol acetals is given. A clean transformation of aromatic and aliphatic substrates is possible with trifluoroacetic acid within 30 min at 0 °C. Glycolacetals derived from ketones (ketals) cannot be converted with this protocol. Deprotection of the pinacol acetals is possible with
摘要 给出了通常用作醛官能团保护基团的乙二醇缩醛的一锅转缩醛转化为更稳定的频哪醇缩醛。在 0 °C 下,使用三氟乙酸可在 30 分钟内实现芳香族和脂肪族底物的彻底转化。从酮(缩酮)衍生的乙二醇缩醛不能用此协议转换。频哪醇缩醛的脱保护可以在水存在下用三氟甲磺酸进行。图形概要
Enantioselective Total Synthesis and Absolute Configuration Assignment of (+)-Toxicodenane A
作者:Xu-Long Qin、Guo-Jie Wu、Fu-She Han
DOI:10.1021/acs.orglett.1c03293
日期:2021.11.5
total synthesis and absolute configuration assignment of (+)-toxicodenane A via a nine-step sequence from the readily available material. The synthesis features a desymmetric enantioselective reduction of 2,2-disubstituted 1,3-cyclohexanedione for the synthesis of a chiral 2,2-disubstituted 3-hydroxy cyclohexanone buildingblock, a highly diastereoselective Grignard reaction for the incorporation of an
我们通过现成材料的九步序列展示了 (+)-toxicodenane A 的第一个对映选择性全合成和绝对构型分配。该合成具有不对称对映选择性还原 2,2-二取代 1,3-环己二酮以合成手性 2,2-二取代 3-羟基环己酮结构单元、高度非对映选择性格氏反应以掺入烯丙基,以及路易斯酸介导的分子内转缩醛化和 Prins 级联反应,用于构建氧杂桥接的双环。