Lactone Synthesis by Enantioselective Orthogonal Tandem Catalysis
作者:Sourabh Mishra、Aaron Aponick
DOI:10.1002/anie.201904438
日期:2019.7.8
In this work, we report enantioselective orthogonal tandem catalysis for the one pot conversion of Meldrum's acid derivatives and alkynes into δ‐lactones. This new transformation, which resembles a formal [4+2] cycloaddition with concomitant decarboxylation and loss of acetone, proceeds in high yields and excellent enantioselectivity (up to 99 % ee) over a broad substrate scope. The products are densely
在这项工作中,我们报道了对映体选择性正交串联催化作用,用于将麦德鲁姆的酸衍生物和炔烃一锅转化为δ-内酯。这种新的转化过程类似于正式的[4 + 2]环加成反应,伴随着脱羧作用和丙酮的损失,在宽的底物范围内都可以高收率和出色的对映选择性(高达99%ee)进行。产物经过密集的官能化处理,已经成熟,可以进行进一步的转化,如开环反应和还原为饱和内酯所示。结果发现,一种新的偶然形成的Ag I -Me-StackPhos复合物可有效催化高度选择性的6-内酰胺dig环化反应,完全逆转了以前在相关系统中报道的区域化学反应。更一般而言,在这项研究中,我们确定了一对可同时运行的炔烃双官能化兼容催化剂,这些催化剂可使炔烃在连续的一锅转换中既充当亲核试剂又充当亲电试剂。
Asymmetric Addition of Alkenylstannanes to Alkylidene Meldrum’s Acids
作者:Stuart J. Mahoney、Aaron M. Dumas、Eric Fillion
DOI:10.1021/ol902216y
日期:2009.11.19
Herein, we describe enantioselective addition of alkenyltin reagents possessing a reactive and sensitive allylic functionality not readilyavailable to other classes of alkenyl metals. This method is enabled by the use of highlyelectrophilic alkylidene Meldrum’s acids as acceptors and a cationic Rh(I)−diene complex as catalyst.
One-pot synthesis of highly substituted tetrahydrofurans from activated propargyl alcohols using Bu3P
作者:Yakambram Pedduri、John S. Williamson
DOI:10.1016/j.tetlet.2008.07.180
日期:2008.10
General and robust synthesis of highly functionalized tetrahydrofuran ring was accomplished with activated propargyl alcohol and reactive Michael acceptors in the presence of catalytic Bu3P.
Synthesis and Characterization of Tricarbastannatranes and Their Reactivity in B(C<sub>6</sub>F<sub>5</sub>)<sub>3</sub>-Promoted Conjugate Additions
作者:Azadeh Kavoosi、Eric Fillion
DOI:10.1002/anie.201500983
日期:2015.4.27
The synthesis and characterization of a series of tricarbastannatranes, in the solid state and in solution, are described. The structures of the complexes [N(CH2CH2CH2)3Sn](BF4), [N(CH2CH2CH2)3Sn](SbF6), [N(CH2CH2CH2)3Sn]4[(SbF6)3Cl], and [(N(CH2CH2CH2)3Sn)2OH][MeB(C6F5)3] were determined by X‐ray crystallography. Furthermore, the B(C6F5)3‐promoted conjugateaddition of alkyl‐tricarbastannatranes to
Alkylidene Meldrum′s Acid as Acceptor‐Donor‐Acceptor with Azomethine Ylide for Organocatalytic Asymmetric (3+2) Cycloaddition/Annulation: Synthesis of Chromeno[4,3‐<i>b</i>]pyrrolidine
作者:Yan‐Cheng Liou、Yi‐Ru Chen、Ching‐Wen Hsu、Xuan‐Rui Huang、Heng‐Wei Wang、Wenwei Lin
DOI:10.1002/adsc.202300609
日期:2023.11.7
A quinine-derived thiourea-catalyzed enantioselective double annulation strategy using alkylidene Meldrum′sacid as an acceptor-donor-acceptor with salicylaldehyde-derived azomethine ylide is reported. The methodology is realized via a (3+2) cycloaddition/transesterification/decarboxylation sequence, giving chromeno[4,3-b]pyrrolidines within 15–420 minutes at room temperature in 51–97% yields with