Synthesis of 2-aryl-3-hydroxymethyl-5,5-difluoropiperidines
摘要:
A strategy toward the synthesis of functionalized 5,5-difluoropiperidines, a class of compounds with potential as building block in medicinal chemistry, was developed. In a three-step procedure 2,2-difluoroglutaric anhydride was synthesized starting from ethyl bromodifluoroacetate. This key intermediate reacts fluently with various imines to yield 5,5-difluoropiperidinone carboxylic acids. Subsequent esterification of the obtained carboxylic acids enabled the isolation of trans-substituted 5,5difluoro-2-arylpiperidinone-3-carboxylates as the major isomers. Reduction of the difluorinated piperidinonecarboxylates using borane gave rise to new trans-2-aryl-1-benzyl-5,5-difluoro-3-hydroxymethylpiperidines in excellent yields. (C) 2012 Elsevier Ltd. All rights reserved.
We have reported that the reaction of ethyl bromodifluoroacetate (1) with alkenyl iodides in the presence of copper powder gives ethyl alkenyldifluoroacetates. As an extension of this reaction, reaction of 1 with Michael acceptors in the presence of copper powder was examined and found to give 1,4-addition products selectively, unless the acceptor has a group stabilizing a radical intermediate, such
Reactions of ethyl bromodifluoroacetate in the presence of copper powder
作者:K. Sato、M. Omote、A. Ando、I. Kumadaki
DOI:10.1016/j.jfluchem.2003.11.023
日期:2004.4
We have examined the reaction of ethyl bromodifluoroacetate (1) in the presence of copper powder as a procedure for the synthesis of compounds containing a CF2 group. The complex formed in the above reaction reacted with vinyl or aryl iodides to give cross-coupling products, with Michael acceptors to give 1,4-addition products and with olefins to give radical addition products. The cross-coupling reaction
Novel Approach toward 3,3-Difluoropiperidines from Easily Available Starting Materials and Synthesis of a New Phosphodiesterase Inhibitor
作者:Mauro Marigo、Jessica Giacoboni、Rasmus Clausen
DOI:10.1055/s-0036-1588313
日期:——
for the synthesis of 3,3-difluoropiperidines has been developed. The target compounds are prepared in three steps using a robust protocol and simple starting materials. The incorporation of the fluorine is achieved by using the cheap and easily available ethyl 2-bromo-2,2-difluoroacetate as building block. Using this methodology, a new potent in vitro phosphodiesterase 2A (PDE2A) inhibitor containing
Reaction of ethyl bromodifluoroacetate with a variety of Michael acceptors was tremendously improved by the addition of TMEDA. Using this additive, 1,4-adducts were formed exclusively, and any 1,2-adducts or radical adducts were not obtained. THF or other low boiling solvents can be used as a solvent. This simplifies the work-up of the reaction effectively. (C) 2003 Elsevier Science B.V. All rights reserved.