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。
Copper(II)-Catalyzed Reactions of α-Keto Thioesters with Azides via C–C and C–S Bond Cleavages: Synthesis of <i>N</i>-Acylureas and Amides
作者:Rajib Maity、Sandip Naskar、Indrajit Das
DOI:10.1021/acs.joc.7b03054
日期:2018.2.16
Cu(II)-catalyzed reaction of α-keto thioesters with trimethylsilyl azide (TMSN3) proceeds with the transformation of the thioester group into urea through C–C and C–S bond cleavages, constituting a practical and straightforward synthesis of N-acylureas. When diphenyl phosphoryl azide (DPPA) is used instead as the azide source in an aqueous environment, primary amides are formed via substitution of
Visible-Light-Activated Divergent Reactivity of Dienones: Dimerization in Neat Conditions and Regioselective <i>E</i> to <i>Z</i> Isomerization in the Solvent
作者:Sandip Naskar、Sabyasachi Roy Chowdhury、Somrita Mondal、Dilip K. Maiti、Sabyashachi Mishra、Indrajit Das
DOI:10.1021/acs.orglett.9b00083
日期:2019.3.15
4-Dienones undergo visible-light-promoted, photocatalyst-free dimerization in neat conditions to provide cyclohexene derivatives stereoselectively through cascade rearrangement pathways, whereas regioselective E → Z isomerization of the more dienophilic doublebond takes place exclusively in nitromethane. On the basis of intermediate isolation and computational DFT studies, the dimerization reaction is proposed
A Torquoselective Thermal 6π‐Electrocyclization Approach to 1,4‐Cyclohexadienes via Solvent‐Aided Proton Transfer: Experimental and Theoretical Studies
作者:Jayanta Saha、Soumadip Banerjee、Sidhartha Malo、Abhijit Kumar Das、Indrajit Das
DOI:10.1002/chem.202304009
日期:2024.3.15
1,4-Cyclohexadienes can be directly synthesized by heating (2E,4E,6E)-hexatrienes in a mixture of toluene/MeOH or EtOH (2 : 1) solvents at 90–100 °C. This is done through a torquoselective disrotatory 6π-electrocyclic ring closure followed by a polar protic solvent-assisted proton-transfer process.
1,4-环己二烯可以通过在甲苯/MeOH或EtOH(2:1)溶剂混合物中于90–100°C下加热( 2E , 4E , 6E )-六三烯直接合成。这是通过扭矩选择性旋转 6π-电环闭合,然后是极性质子溶剂辅助的质子转移过程来完成的。