Solution-, Solid-Phase, and Fluorous Synthesis of β,β-Difluorinated Cyclic Quaternary α-Amino Acid Derivatives: A Comparative Study
作者:Santos Fustero、María Sánchez-Roselló、Vanessa Rodrigo、Juan F. Sanz-Cervera、Julio Piera、Antonio Simón-Fuentes、Carlos del Pozo
DOI:10.1002/chem.200702009
日期:2008.8.8
The diastereoselective synthesis of cyclic beta,beta-difluorinated alpha-amino acid derivatives bearing a quaternary stereocenter is described. The process relies on the chemo- and diastereoselective addition of allylic organometallic reagents to fluorinated alpha-imino esters and a subsequent ring-closingmetathesis reaction (RCM). Complete selectivity in the nucleophilic addition was achieved with
Cross-Metathesis Reactions as an Efficient Tool in the Synthesis of Fluorinated Cyclic β-Amino Acids
作者:Santos Fustero、María Sánchez-Roselló、José Luis Aceña、Begoña Fernández、Amparo Asensio、Juan F. Sanz-Cervera、Carlos del Pozo
DOI:10.1021/jo900296d
日期:2009.5.1
The synthesis of enantiomerically pure, cyclic, γ,γ-difluorinated β-amino acids with various ring sizes has been carried out with a cross-metathesis (CM) reaction being one of the key steps, followed by a Dieckmann-type condensation to bring about the cyclization. Subsequent catalytic hydrogenation under microwave irradiation with (−)-8-phenylmenthol as a chiral auxiliary led to the successful chemo-