Stereoselective Dehydroxyboration of Allylic Alcohols to Access (<i>E</i>)-Allylboronates by a Combination of C–OH Cleavage and Boron Transfer under Iron Catalysis
Iron-catalyzed direct SN2′ dehydroxyboration of allylic alcohols has been developed to access (E)-stereoselective allylboronates. Allylic alcohols with diverse structures and functional groups, especially derived from natural products, underwent smooth transformation. The six-membered ring transition state formed by allylic alcohols and iron–boron intermediate was indicated to be the key component
铁催化的烯丙醇直接 S N 2' 脱羟基硼酸已被开发用于获得 ( E )-立体选择性烯丙基硼酸酯。具有多种结构和官能团的烯丙醇,特别是来自天然产物的烯丙醇,经历了平稳的转变。由烯丙醇和铁-硼中间体形成的六元环过渡态被证明是参与硼基团转移、C-OH键活化和立体选择性控制的关键成分。
Catalytic enantioselective rearrangement of meso-epoxides mediated by chiral lithium amides in the presence of excess cross-linked polymer-bound lithium amides
作者:Atsushi Seki、Masatoshi Asami
DOI:10.1016/s0040-4020(02)00371-x
日期:2002.6
Insoluble polymer-bound achiral lithium dialkylamides were prepared from the corresponding cross-linked polymer-bound amines and butyllithium. The polymer-bound achiral reagent was applied to a catalytic enantioselective rearrangement of meso-epoxides as an in situ regenerating agent of a chiral lithiumamide. The efficiency of the catalytic system was improved, and chiral allylic alcohol derivatives
The Co-catalyzed remote hydroboration and alkene isomerization of allylic siloxanes were realized by a ligand-controlled strategy. The remote hydroboration with dcype provided borylethers, while xantphos favored the formation of silyl enol ethers.
An efficient reductive Claisen rearrangement, catalyzed by in situ generated copper hydride and stoichiometric in diethoxymethylsilane, has been developed. Yields of up to 95 % with good to excellent diastereoselectivities were observed in this reaction. Mechanistic studies showed that the stereospecific rearrangement proceeded via a chair transition state of (E)‐silyl ketene acetals as intermediates
Neue Alkenole(I), Verfahren zu deren Herstellung, Verwendung von (I) als Riechstoffe und Riechstoffkompositionen mit einem Gehalt an (I)
申请人:L. GIVAUDAN & CIE Société Anonyme
公开号:EP0086945A1
公开(公告)日:1983-08-31
Die Erfindung betrifft neue Riechstoffe, nämlich neue Alkohole der allgemeinen Formel.
worin R1 für Wasserstoff und R2 für geradkettiges oder endständig einmal verzweigtes C5-7-Alkyl oder C4-7-Alkenyl steht, oder R1 Methyl und R2 geradkettiges oder endständig einmal verzweigtes C4-7-Alkyl darstellt.
Die Erfindung betrifft auch Riechstoffkompositionen mit einem Gehalt an Verbindungen I, ein Verfahren zur Herstellung der Verbindungen I und die Verwendung der Verbindungen I als Riechstoffe.
本发明涉及新的气味剂,即通式如下的新醇
其中R1为氢,R2为直链或末端一次支链的C5-7-烷基或C4-7-烯基,或R1为甲基,R2为直链或末端一次支链的C4-7-烷基。
本发明还涉及含有化合物 I 的气味剂组合物、制备化合物 I 的工艺以及将化合物 I 用作气味剂的用途。