Enantioselective synthesis of sec-allylalcohols by catalytic asymmetric addition of divinylzinc to aldehydes.
作者:Wolfgang Oppolzer、Rumen N. Radinov
DOI:10.1016/s0040-4039(00)80834-5
日期:——
Readily available chiral tridentate ligand catalyzes the highly Si-face selective addition of diethyl-, di-n-propylzinc and, more significantly, of divinylzinc to aromatic and aliphatic aldehydes whereas bidentate ligands and exert a topologically reversed catalytic bias.
Synthesis of α,α′-Disubstituted Linear Ethers by an Intermolecular Nicholas Reaction - Application to the Synthesis of (+)-<i>cis</i>/(-)-<i>trans</i>-Lauthisan and (+)-<i>cis</i>/(+)-<i>trans</i>-Obtusan
作者:Nuria Ortega、Tomás Martín、Víctor S. Martín
DOI:10.1002/ejoc.200801063
日期:2009.2
A new and efficient methodology to prepare α,α′-disubstituted linear ethers through an intermolecular Nicholas reaction (interNR) is described. cis-2,8-Disubstituted oxocanes, cis-2,9-disubstituted oxonanes, their trans isomers, and their parent unsaturated precursors were prepared from the corresponding Co2(CO)6–cycloalkynic ethers. Key steps in such syntheses were the ether linkage formation by interNR
Catalytic asymmetric epoxidation and kinetic resolution: modified procedures including in situ derivatization
作者:Yun Gao、Janice M. Klunder、Robert M. Hanson、Hiroko Masamune、Soo Y. Ko、K. Barry Sharpless
DOI:10.1021/ja00253a032
日期:1987.9
The use of 3A or 4A molecularsieves (zeolites) substantially increases the scope of the titanium(IV)-catalyzed asymmetricepoxidation of primary allylicalcohols. Whereas without molecularsievesepoxidations employing only 5 to 10 mol % Ti(O-i-Pr)/sub 4/ generally lead to low conversion or low enantioselectivity, in the presence of molecularsieves such reactions generally lead to high conversion
A new and efficient total synthesis of (−)-pseudophrynaminol, the pyrrolo[2,3-b]indolealkaloid bearing the allylic moiety at the 3a-position, has been achieved by a sequence involving 3-allylindol-2-one 8 as a key intermediate. The enantioselective construction of the quaternary carbon in 8 was performed through a tandemcascade reaction of 2-allyloxyindolin-3-one 4, olefination, isomerization, and
( - ) -的一种新的和有效的总合成pseudophrynaminol中,吡咯并[2,3- b ]吲哚生物碱轴承在图3a-位置烯丙基部分,已经通过涉及3- allylindol -2-酮的序列来实现8如关键中间体。通过2-烯丙氧基吲哚-3-一4的串联级联反应,烯化,异构化和不对称克莱森重排进行8中四元碳的对映选择性结构。
An Approach to <i>Lauroxanes</i> by Iterative Use of Co<sub>2</sub>(CO)<sub>6</sub>-Acetylenic Complexes. A Formal Synthesis of (+)-Laurencin
作者:Nuria Ortega、Victor S. Martín、Tomás Martín
DOI:10.1021/jo101566x
日期:2010.10.1
Nicholas reaction to form unsaturated branched linear ethers, a ring closing metathesis to obtain the cobalt complex cyclic ethers, and an isomerization promoted by montmorillonite K-10. A short synthesis of cyclic ethers of seven-, eight-, and nine-memberedrings is described. Additionally, the methodology is exemplified by the formal synthesis of (+)-laurencin, a red algae metabolite.