Towards organo-click reactions: development of pharmaceutical ingredients by using direct organocatalytic bio-mimetic reductions
作者:Dhevalapally B. Ramachary、G. Babul Reddy
DOI:10.1039/b612611a
日期:——
Economic and environmentally friendly bio-mimetic one-pot three and four-component Knoevenagel–hydrogenation (K–H), five-component Knoevenagel–hydrogenation–alkylation (K–H–A) and six-component Knoevenagel–hydrogenation–alkylation–Huisgen cycloaddition (K–H–A–HC) reactions of aldehydes, CH-acids, o-phenylenediamine, alkyl halides and azides using proline, proline–metal carbonate and proline–metal carbonate–CuI-catalysis, respectively have been developed. Many of K–H and K–H–A compounds have direct application in pharmaceutical chemistry.
Ethynyl-1,2-benziodoxol-3(1 H)-one (EBX): An Exceptional Reagent for the Ethynylation of Keto, Cyano, and Nitro Esters
作者:Davinia Fernández González、Jonathan P. Brand、Jérôme Waser
DOI:10.1002/chem.201001539
日期:2010.8.16
Hot alkyne! The in situ generation of ethynyl‐1,2‐benziodoxol‐3(1H)‐one (EBX) from a silyl‐protected reagent by using TBAF is reported. EBX displayed exceptional acetylene transfer ability onto stabilizedenolates (see scheme), even at −78 °C. The mild reaction conditions allowed the first ethynylation reactions of linear keto, cyano, and nitro esters in high yields to give all‐carbon quaternary centers
<i>tert</i>-Butoxide-Mediated Arylation of 2-Substituted Cyanoacetates with Diaryliodonium Salts
作者:Xiaofei Qian、Jianwei Han、Limin Wang
DOI:10.1002/adsc.201501013
日期:2016.3.17
A transition metal‐free direct arylation of 2‐substituted cyanoacetates with diaryliodoniumsalts was developed. With this approach, a wide range of α‐tolunitrile derivatives has been synthesized in good to excellent yields of 45–92%. Furthermore, the practicability of this approach is further manifested in the synthesis of a related bioactive agent of glutarimide.
condensation–reduction approach, which was carried out in water, has been reported. Using Hantzsch esters as reducing agent, under the promotion of base, a variety of reduced Knoevenagel adducts could be easily prepared by direct alkylation of malononitrile, ethyl 2-cyanoacetate, and 2-(4-nitrophenyl)acetonitrile, respectively. Meanwhile, a gram-scale synthesis of the protocol was also realized with excellent
Room Temperature, Reductive Alkylation of Activated Methylene Compounds: Carbon–Carbon Bond Formation Driven by the Rhodium-Catalyzed Water–Gas Shift Reaction
作者:Scott E. Denmark、Malek Y. S. Ibrahim、Andrea Ambrosi
DOI:10.1021/acscatal.6b03183
日期:2017.1.6
The rhodium-catalyzed water–gas shift reaction has been demonstrated to drive the reductive alkylation of several classes of activated methylene compounds at room temperature. Under catalysis by rhodium trichloride (2–3 mol %), carbon monoxide (10 bar), water (2–50 equiv), and triethylamine (2.5–7 equiv), the scope has been successfully expanded to cover a wide range of alkylating agents, including