Direct Carbon−Carbon Bond Formation via Soft Enolization: A Facile and Efficient Synthesis of 1,3-Diketones
摘要:
Ketones undergo soft enolate formation and acylation on treatment with MgBr2 center dot OE2, i-Pr2NEt, and various acylating agents to give 1,3-diketones. The process is particularly efficient for N-acylbenzotriazoles and O-Pfp esters, and, in these cases, is conducted with untreated, reagent-grade CH2Cl2 open to the air, thus providing an exceptionally simple approach to the synthesis of this important class of compounds.
Transition-Metal-Free Formal Decarboxylative Coupling of α-Oxocarboxylates with α-Bromoketones under Neutral Conditions: A Simple Access to 1,3-Diketones
作者:Zhen He、Xiaotian Qi、Shiqing Li、Yinsong Zhao、Ge Gao、Yu Lan、Yiwei Wu、Jingbo Lan、Jingsong You
DOI:10.1002/anie.201409361
日期:2015.1.12
A transition‐metal‐free formaldecarboxylativecoupling reaction between α‐oxocarboxylates and α‐bromoketones to synthesize 1,3‐diketone derivatives is presented. In this reaction, a broad scope of substrates can be employed, and neither a metal‐based reagent nor an additional base is required. DFT calculations reveal that this reaction proceeds through a coupling followed by decarboxylation mechanism
Ketones undergo soft enolization and acylation on treatment with MgBr2·OEt2, i-Pr2NEt, and various acylating agents to give 1,3-diketones. The process is particularly efficient for N-acylbenzotriazoles and O-pentafluorophenyl esters, and, in these cases, is conducted using untreated, reagent grade CH2Cl2 open to the air, thus providing an exceptionally simple approach to the synthesis of this important class of compounds.
Room-Temperature Coupling/Decarboxylation Reaction of α-Oxocarboxylates with α-Bromoketones: Solvent-Controlled Regioselectivity for 1,2- and 1,3-Diketones
作者:Zhen He、Xiaotian Qi、Zhijie She、Yinsong Zhao、Shiqing Li、Junbin Tang、Ge Gao、Yu Lan、Jingsong You
DOI:10.1021/acs.joc.6b02575
日期:2017.2.3
A transition-metal-free and room-temperature coupling/decarboxylation reaction between α-oxocarboxylates and α-bromoketones is reported herein. It represents the first mild and regioselective synthesis of either 1,2- or 1,3-diketones from the same starting materials. Notably, the regioselectivity is simply controlled by solvents. The preliminary experimental data and DFT calculations suggest sequential
An effective phosphine-catalyzed protocol has been established for the syntheses of 1,3-diketones and nitriles from alkynones with oximes as hydroxide surrogates. This method features the use of a phosphine catalyst, compatibility with various functional groups and ambient temperature, which makes this approach very practical. A plausible mechanism was proposed.
Catalyst-free Tandem 1,3-Dipolar Cycloaddition/Aldol Condensation: Diastereoselective Construction of the Azatetraquinane Skeleton
作者:Nikolay S. Zimnitskiy、Andrey D. Denikaev、Alexey Y. Barkov、Igor B. Kutyashev、Vladislav Y. Korotaev、Vyacheslav Y. Sosnovskikh
DOI:10.1021/acs.joc.0c01127
日期:2020.7.2
The one-potregioselective and diastereoselective method for the synthesis of 5-(het)aroyl-7-(het)arylhexahydrobenzo[4,5]pentaleno[1,6a-b](thia)pyrrolizine-6,12-diones from accessible 1,5-di(het)arylpent-4-ene-1,3-diones or curcuminoids in 38–98% yield was developed. This reaction proceeds as a sequence of 1,3-dipolar cycloaddition of azomethine ylide generated in situ from ninhydrin and (thia)proline
一锅区域选择性和非对映选择性的方法,从中合成5- (杂)芳酰基-7-(杂)芳基六氢苯并[4,5]戊烯[1,6 a - b ](硫代)吡咯烷嗪-6,12-二酮可开发的1,5-二(杂)芳基戊-4-烯-1,3-二酮或姜黄素的产率为38-98%。该反应按顺序进行,由茚三酮和(硫代)脯氨酸在相应的二烯二酮的C═C键上原位生成的偶氮甲嘧啶1,3-偶极环加成,随后自发的分子内羟醛缩合,导致氮杂四喹烷的形成。脚手架。