Synthesis of enones, pyrazolines and pyrrolines with <i>gem</i>-difluoroalkyl side chains
作者:Assaad Nasr El Dine、Ali Khalaf、Danielle Grée、Olivier Tasseau、Fares Fares、Nada Jaber、Philippe Lesot、Ali Hachem、René Grée
DOI:10.3762/bjoc.9.230
日期:——
Starting from easily accessible gem-difluoropropargylic derivatives, a DBU-mediated isomerisation affords enones in fair yields with a gem-difluoroalkyl chain. These derivatives were used to prepare pyrazolines and pyrrolines with the desired gem-difluoroalkyl side chain by cyclocondensations in good yields and with excellent stereoselectivity. A one-pot process was also successfully developed for these sequential reactions. By carrying out various types of Pd-catalyzed coupling reactions for compounds with a p-bromophenyl substituent a route to focused chemical libraries was demonstrated.
propargylic fluoride (+)-12 with ethylene affords the enantioenriched 1,3-diene (+)-14 having fluorine-containing side chain at 2-position in good yield. Upon Diels-Alder reaction, followed by aromatization, this diene affords the new benzylic fluorides (+)-16 and (+)-17 in high ee values. This new strategy has been successfully extended to the corresponding gem-difluoro diene 21 and benzylic fluorides 23 and
Synthesis of new difluoroalkyl propargylic ketones and their use for the preparation of fluorinated heterocycles
作者:Pierre Bannwarth、Danielle Grée、René Grée
DOI:10.1016/j.tetlet.2010.02.116
日期:2010.5
Synthetic methodology studies are reported towards the preparation of new propargylic ketones with CF2R side chains. These molecules are used for the synthesis of various types of five- or six-membered heterocycles with difluoroalkyl side chains.
Synthesis of Fluorine-Containing Exoalkylidene β-Lactams
作者:Assaad Nasr El Dine、Danielle Grée、Thierry Roisnel、Elsa Caytan、Ali Hachem、René Grée
DOI:10.1002/ejoc.201501347
日期:2016.1
The Kinugasa reaction, applied to propargylic gem-difluorides, allows a very direct and efficient synthesis of new exoalkylideneβ-lactams with a fluorine in the vinylic position.