A direct Csp3–H bond oxidative thioesterification of methyl ketones with aromatic thiols/disulfides promoted by TBAI/K2S2O8 has been developed. The reaction provides successfully a simple and efficientmethod for the synthesis of functionalized α-ketothioesters of aromatic thiols. This practical methodology exhibits readily available starting materials, large-scale applicability, synthetic application
已经开发了由TBAI / K 2 S 2 O 8促进的甲基酮与芳族硫醇/二硫化物的直接C sp3- H键氧化硫酯化反应。该反应成功地提供了一种简单而有效的方法来合成芳族硫醇的官能化α-酮硫酯。这种实用的方法论展示了容易获得的起始原料,大规模的适用性,合成的应用以及广泛的官能团耐受性。提出了一种可能的转换机制。
α-Keto Thioesters as Building Blocks for Accessing γ-Hydroxybutenolides and Oxazoles
作者:Kanchan Mal、Indrajit Das
DOI:10.1002/adsc.201700329
日期:2017.8.7
found to react differently with β‐keto esters and isocyanoacetates. They undergo base induced Knoevenagel‐type condensation on the keto carbonyl group with β‐keto esters, followed by intramolecular cyclization and water addition leads to highly substituted γ‐hydroxybutenolides. On the other hand, substituted oxazole derivatives have been obtained using isocyanoacetates via nucleophilic displacement on the
Direct Access to 2-Thioxooxazolidin-4-ones and Oxazolidine-2,4-diones from α-Keto Thioesters through Thiolate Transfer
作者:Rajib Maity、Sandip Naskar、Kanchan Mal、Sandipa Biswas、Indrajit Das
DOI:10.1002/adsc.201701020
日期:2017.12.19
We report a direct synthesis of 2‐thioxooxazolidin‐4‐ones and oxazolidine‐2,4‐diones from α‐keto thioesters with sodium thiocyanate or potassiumcyanate, respectively. The reactions proceed through nucleophilic substitution of a thioester with thiocyanate/cyanate anion, thiolate anion addition to carbonyl carbon, and subsequent intramolecular C−O heterocyclization.
Transition‐Metal‐Free Reduction of
<i>α</i>
‐Keto Thioesters with Hydrosilanes at Room Temperature: Divergent Synthesis through Reagent‐Controlled Chemoselectivities
作者:Rajib Maity、Bhanuranjan Das、Indrajit Das
DOI:10.1002/adsc.201900222
日期:2019.5.14
acid as a promoter can be used for the reagent‐controlled chemoselective reduction at room temperature of conjugated C=C bond, enone moiety, or the carbonyl of (β,γ‐unsaturated) α‐keto thioesters, providing facile access to β,γ‐saturatedα‐keto thioesters, α‐hydroxy thioesters, or silyl ethers. The reaction pathway and the chemoselectivity can be fine‐tuned through the judicious choice of the hydrosilane
氢硅烷与布朗斯台德酸或路易斯酸作为促进剂的组合可用于在室温下进行试剂控制的化学选择还原反应,以还原共轭C = C键,烯酮部分或(β,γ-不饱和)α-酮的羰基硫酯,可轻松获得β,γ-饱和的α-酮硫代酯,α-羟基硫代酯或甲硅烷基醚。可以通过明智地选择氢化硅烷或反应条件来微调反应途径和化学选择性。该反应可耐受包括不稳定的硫酯在内的各种官能团,并且通常以中等至极好的收率获得产物。不对称硫醚也可以使用PMHS和催化性B(C 6 F 5)3合成通过两个羰基的还原性脱氧。β,γ-不饱和α-羟基硫代酯和β,γ-饱和α-酮硫代酯的饱和α-酮酰胺的胺介导和无偶联剂的合成突出了其适用性。
Tandem Chemoselective 1,2-/1,4-Migration of the Thio Group in Keto Thioesters: An Efficient Approach to Substituted Butenolides
作者:Kanchan Mal、Sandip Naskar、Shovan Kumar Sen、Ramalingam Natarajan、Indrajit Das
DOI:10.1002/adsc.201600640
日期:2016.10.20
We report herein an efficient and mechanistically unique tandem chemoselective 1,2‐/1,4‐migration of the thio group in keto thioesters that provides substitutedbutenolides in moderate to excellent yields. Thus, α‐keto thioesters in the presence of stabilized phosphonate carbanions undergo tandem 1,2‐sulfur migration; whereas 1,4‐migration of the thio group has been achieved with the same thioesters