Catalytic Asymmetric [3+2] Annulation of Allylsilanes with Isatins: Synthesis of Spirooxindoles
作者:Nadine V. Hanhan、Nicolas R. Ball-Jones、Ngon T. Tran、Annaliese K. Franz
DOI:10.1002/anie.201105739
日期:2012.1.23
Silyl‐inspired spirocycle: The title reaction is the first example of a catalytic asymmetric [3+2] annulation reaction with allylsilanes. The annulation reaction utilizes a chiral ScCl2(SbF6)/L catalyst and TMSCl as a promoter to afford spirooxindoles in excellent enantioselectivity at room temperature. The SiC bond can be oxidized to deliver hydroxy‐substituted spirooxindoles. TMS=trimethylsilyl
A highly diastereo- and enantioselective allylation of isatins with 3-substituted allylboronic compounds was achieved by the chiral N,N′-dioxide/Lu(OTf)3 complex. This approach provides an efficient route to useful enantioenriched 3-allyl-3-hydroxyoxindoles with adjacent tetrasubstituted tertiary or tetrasubstituted quaternary stereogenic centers. Density functional theory calculations were performed
Stereoselective Synthesis of 1-Methyl-3′,4′,5′,6′-tetrahydrospiro[indoline-3,2′-pyran]-2-one Derivatives via Prins Cyclization
作者:Krishna Damera、Bingchen Yu、Binghe Wang
DOI:10.1021/acs.joc.5b00249
日期:2015.6.5
spirocyclization has been developed for the construction of functionalized spirooxindole pyran viaLewisacidpromoted Prins cyclization. The reaction proceeds through formation of a single diastereoisomer with high stereoselectivity. This approach can be used to construct biologically important substituted spirooxindole as well as fluorinated pyran scaffolds.
Scandium(III)-Catalyzed Enantioselective Allylation of Isatins Using Allylsilanes
作者:Nadine V. Hanhan、Yng C. Tang、Ngon T. Tran、Annaliese K. Franz
DOI:10.1021/ol300496v
日期:2012.5.4
The scandium(III)-catalyzed enantioselective Hosomi-Sakurai allylation of isatins with various substituted allylic silanes is described. A catalyst loading as low as 0.05 mol % Is utilized at room temperature to afford the 3-allyl-3-hydroxy-2-oxindoles in excellent yields and enantioselectivity up to 99% ee, including a demonstration of a gram-scale reaction. The effects of additives and varying silyl groups were explored to demonstrate the scope and application.
A Hg(ClO<sub>4</sub>)<sub>2</sub>·3H<sub>2</sub>O Catalyzed Sakurai–Hosomi Allylation of Isatins and Isatin Ketoimines Using Allyltrimethylsilane
作者:Zhong-Yan Cao、Yan Zhang、Cong-Bin Ji、Jian Zhou
DOI:10.1021/ol202705g
日期:2011.12.16
It is reported that Hg(ClO4)(2)center dot 3H(2)O could efficiently activate the cheap but less reactive allyltrimethylsilane for the allylation of isatins or isatin ketoimines, with catalyst loading down to 0.1 mol %. This is the first example of Sakurai-Hosomi allylation of ketoimines using allyltrimethylsilane. A rare example of chiral mercury catalysis is also reported.