通过在磷腈和腈官能团之间发生不寻常的氮杂-维蒂希反应并提供吡咯衍生的亚氨基磷腈,进行了α-EWG取代(吸电子基团,EWG)γ-叠氮基丁腈的转化。发现α-EWGs控制化学选择性,并取决于其性质,在氮杂-Wittig反应中充当CN基团活化剂(例如,酯,酰胺或腈)或竞争剂(例如,酮)。为了证明所得亚氨基磷腈作为N,N-双亲核试剂的合成效用,将其转化为吡咯稠合体系,即吡咯并[1,2- a ]咪唑和吡咯并[1,2- a ] [1,3]二氮杂s。执行。
通过在磷腈和腈官能团之间发生不寻常的氮杂-维蒂希反应并提供吡咯衍生的亚氨基磷腈,进行了α-EWG取代(吸电子基团,EWG)γ-叠氮基丁腈的转化。发现α-EWGs控制化学选择性,并取决于其性质,在氮杂-Wittig反应中充当CN基团活化剂(例如,酯,酰胺或腈)或竞争剂(例如,酮)。为了证明所得亚氨基磷腈作为N,N-双亲核试剂的合成效用,将其转化为吡咯稠合体系,即吡咯并[1,2- a ]咪唑和吡咯并[1,2- a ] [1,3]二氮杂s。执行。
the presence of TMSCN and an alcohol additive are catalyzed by nucleophilicphosphines. The trisubstituted E-olefin products of anti-addition of hydrogen cyanide to the alkyne are produced with high regio- and stereoselectivity. The alcohol additive reacts with TMSCN to produce hydrogen cyanide in situ. Ynoic acids undergo the phosphine catalyzed hydrocyanation in the presence of TMSCN under aprotic
A series of novel N-methyl morpholine (Nmm) based ionic liquids with 1,2-propanediol group were synthesized and used as catalysts for Knoevenagel condensation at roomtemperature in water. Under the effect of the catalyst, various aldehydes or aliphatic ketones could react with a wide range of activated methylene compounds well, including malononitrile, alkyl cyanoacetate, cyanoacetamide, β-diketone
Chiral urea-catalyzed enantioselective epoxidation of α, β-unsaturated esters
作者:Nan Ji、Qinqin Tian、Qingqing Yang、Minghua Li、Wei He
DOI:10.1016/j.tetlet.2021.152909
日期:2021.3
A highly enantioselectiveepoxidation of trans-α-cyano-α, β-unsaturated esters has been described by using cinchona alkaloid-derived urea and H2O2 as the organocatalysts and oxidant, giving chiral glycidic ester derivatives containing cyano groups in good yields (up to 95%) with excellent enantioselectivities (up to 97% ee). A plausible transition state was also proposed.
A highlyenantioselective organocatalytic domino Michael/aldol reaction is presented. The reaction is catalyzed by chiral amines and gives access to highlyfunctionalizedcyclohexanes with one all-carbon quaternary stereocenter and multiple chiral stereocenters in high yields and 83–98% ee.
Microbial transformation of Knoevenagel adducts by whole cells of Brazilian marine-derived fungi: A green approach to remove organic compounds from the aqueous medium
作者:Lucas Lima Zanin、Thayane Melo de Queiroz、André Luiz Meleiro Porto
DOI:10.1080/10242422.2022.2145556
日期:——
Herein, we report the use of whole cells of Brazilian marine-derived fungi in the biotransformation and biodegradation of organiccompounds, particularly, Knoevenagel adducts. A preliminary screeni...