α-dihalogeno β-hydroxy esters or amides by using commercially available Noyori’s complex [RuCl(p-cymene)(R,R)-TsDPEN] as a catalyst (S/C = 100−200) in the asymmetrictransferhydrogenation of the corresponding ketones. Moderate to high yields (up to 99%) and excellent enantioselectivities (up to >99% ee) were achieved for a series of variously substituted dichloro and difluoro β-hydroxy esters and amides.
通过使用市售的Noyori配合物[RuCl(p- Cymene)(R,R)-TsDPEN]作为催化剂(S / C = 100-200)在相应的酮的不对称转移氢化中。对于一系列不同取代的二氯和二氟β-羟基酯和酰胺,可实现中等至高收率(高达99%)和出色的对映选择性(高达> 99%ee)。
An efficient one-pot four-step domino reaction for the synthesis of C2-substituted 3-methylcyclohex-2-enones
An efficient one-pot four-step domino reaction of substituted beta-ketoesters has been optimized giving rise to a large panel of C2-substituted 3-methylcyclohex-2-enones, an important scaffold for the preparation of various initiators for cationic or radical cyclizations. The developed methodology is quite general and applicable to a wide range of beta-ketoester substrates, allowing the introduction of various functionalities at the C2 position of the 3-methylcyclohex-2-enones, in good to excellent yields. (C) 2010 Elsevier Ltd. All rights reserved.
Copper/Silver-Cocatalyzed Conia-Ene Reaction of Linear β-Alkynic β<i>-</i>Ketoesters
作者:Chen-Liang Deng、Ren-Jie Song、Sheng-Mei Guo、Zhi-Qiang Wang、Jin-Heng Li
DOI:10.1021/ol7023289
日期:2007.11.1
A novel and general copper/silver catalytic system has been developed for the Conia-ene intramolecular reaction of linear beta-alkynic beta-ketoesters. In the presence of (CuOTf)(2)center dot C6H6 and AgSbF6 (or AgOAc), a variety of the linear 6-alkynic 6-ketoesters selectively underwent the Conia-ene intramolecular reaction in moderate to good yields.
New Cobalt-Catalyzed Cycloisomerization of ε-Acetylenic β-Keto Esters. Application to a Powerful Cyclization Reactions Cascade
type reaction of epsilon-acetylenic beta-keto esters to form highly functionalized methylenecyclopentanes are described. The observed regio-, chemo-, and stereoselectivities support a process of cycloisomerization which controls the relative stereochemistry of two contiguous stereogenic centers. An efficient route to the basic skeleton of the phyllocladane family has been achieved via a one-pot sequence
Gallium(<scp>III</scp>)- and calcium(<scp>II</scp>)-catalyzed Meyer–Schuster rearrangements followed by intramolecular aldol condensation or endo-Michael addition
calcium-catalyzed Meyer-Schuster rearrangements are described. Under substrate control, the incipient conjugated ketones can be trapped intramolecularly by beta-keto esters or amides to yield cyclic products after aldol condensation or endo-Michael addition. An interesting additive effect that promotes the latter tandem process with calcium has been found.