Preparation of Cyclic .ALPHA.-Hydroxy Ketones from .DELTA.- and .EPSILON.-Keto Acids Induced by the Generation of a Novel Acyl Anion Equivalent from the Carboxyl Group.
An improved method for the transformation of keto acids into cyclic α-hydroxy ketones, induced by the electrochemical generation of a novel acyl anion equivalent from the carboxy group, has been developed. Both five- and six-membered rings were constructed by constant-current electrolysis of δ- and ε-keto acids in the presence of Bu3P using an undivided cell equipped with a graphite anode and a Pt cathode. Attempts to prepare four- and seven-membered ring carbocycles were unsuccessful. The electrochemical reaction was found to be highly stereoselective when cyclization took place onto cyclopentanone and substituted cyclohexanone rings. Stereochemical aspects of the formation of bicyclic products, especially those having a bicyclo[4.3.0]skeleton, are discussed.
Generation of acyl anion equivalents by in situ cathodic reduction of acyl tributylphosphonium ions anodically generated from tributylphosphine and carboxylic acids: preparation of α-hydroxy cycloalkanones from keto acids
The preparation of α-hydroxy cycloalkanones from keto acids was effectively achieved by constant current electrolysis in the presence of Bu3P in an undivided cell under an N2 atmosphere, where the α-oxy ylides generated by the in situ cathodic reduction of acyl tributylphosphonium ions, formed anodically from tributylphosphine and carboxylic acids, seems to function as a novel acyl anion equivalent.
Electroreductive intramolecular coupling of γ- and δ-cyanoketones
作者:Tatsuya Shono、Naoki Kise
DOI:10.1016/s0040-4039(00)88791-2
日期:1990.1
Electroreduction of γ- and δ-cyanoketones in i-PrOH gave cyclized products α-hydroxyketones and their dehydroxylated ketones, and this reaction was applied to the synthesis of dihydrojasmone, methyl dihydrojasmonate, and Rosaprostol.
Cp2TiPh-coordinated cyano and ester groups as efficient ketyl radical acceptors in the reductive radical cyclization of γ- and δ-cyano ketones and δ-keto esters
作者:Yoshihiko Yamamoto、Daisuke Matsumi
DOI:10.1039/a800661j
日期:——
Cp2TiPh promotes the reductive radical cyclization of γ- and δ-cyano ketones and δ-keto esters to give α-hydroxycycloalkanones in moderate to good yields; the titanium reagent coordinates to both the ketone and the cyano or ester terminus, the LUMO of the cyano or ester group is thus lowered, and cyclization proceeds irreversibly without formation of the unstable iminyl or alkoxy radical intermediates.
Application of Biocatalytic Reductive Amination for the Synthesis of a Key Intermediate to a CDK 2/4/6 Inhibitor
作者:Shengquan Duan、Daniel W. Widlicka、Michael P. Burns、Rajesh Kumar、Ian Hotham、Jean-Nicolas Desrosiers、Paul Bowles、Kris N. Jones、Lindsay D. Nicholson、Michele T. Buetti-Weekly、Lu Han、Jeremy Steflik、Eric Hansen、Cheryl M. Hayward、Holly Strohmeyer、Sébastien Monfette、Scott C. Sutton、Christopher Morris
DOI:10.1021/acs.oprd.1c00255
日期:2022.3.18
Biocatalytic reductiveamination catalyzed by engineered imine reductase (RedAms) is a new and powerful tool for the synthesis of substituted chiral amines. Herein, we describe a streamlined synthesis of compound 3, a key intermediate to a CDK 2/4/6 inhibitor 1, relying on the enzymatic reductiveamination of a hydroxyketone to introduce the chiral secondary amine with high diastereoselectivity. The
工程亚胺还原酶(RedAms)催化的生物催化还原胺化是合成取代手性胺的一种新的强大工具。在此,我们描述了化合物 3 的流线型合成,化合物3是 CDK 2/4/6 抑制剂1的关键中间体,依靠羟基酮的酶还原胺化来引入具有高非对映选择性的手性仲胺。还介绍了通过钛催化还原环化改进的羟基酮前体合成和两个 S N Ar 反应过程中的工艺开发3。