Preparation of Sugar β‐Amino Acid Derivatives with Cyclic Structures by Ring‐Closing Metathesis

Abstract

Efficient syntheses of β-amino acid derivatives with cyclic structures were developed. The key steps involve azaMichael addition and ruthenium-catalyzed allylation for the construction of new acyclic β-amino acid dienes incorporat-

A Theoretical Investigation into the Luminescent Properties of d8‐Transition‐Metal Complexes with Tetradentate Schiff Base Ligands

“…Notably, nine‐membered rings were obtained under similar conditions starting from a single β‐amino acid residue upon RCM involving a terminal allyl ester and an N ‐allyl motif 50. This is probably due to fewer steric constraints in the β‐amino acid ester than the two sterically crowded allyl groups in II , which are present on the two Cα carbon atoms in the dipeptide, or to catalyst inhibition by chelation of the amido groups to the metal center.…”

“…Upon reaction of ester 1 50 with trifluoroacetic acid (TFA) in CH 2 Cl 2 at room temperature, salt 2 was obtained in quantitative yield, whereas upon treatment of ester 3 50 with LiOH in a mixture of THF/MeOH/H 2 O (3:1:1 vol. ratio), acid 4 was obtained in 93 % yield.…”

“…Introduction of the allylic group to the ester was then performed by ruthenium‐catalyzed allylic substitution under mild conditions in the presence of [RuCp*(MeCN) 3 ]PF 6 (3 mol‐%, Cp* = C 5 Me 5 ) and Cs 2 CO 3 as the base at room temperature to afford diallylated β‐dipeptide III in 65 % yield. The method used in the last step, which operates without racemization, has been used in the N ‐ and O ‐allylation of α‐ and β‐amino acids 50,56…”

“…We recently reported the synthesis of seven‐ and nine‐membered systems by ring‐closing metathesis50 from β‐amino acids with C ‐, O ‐, and N ‐allylic substituents and having a carbohydrate side chain at the Cβ position. This study revealed the impact of the structure of the substrate with respect to the outcome of the reaction.…”

Metathetic Synthesis of Common and Medium-Sized Lactones: The State of the Art

“…In 2008, the synthesis of α-and β-glucopyranosyl serine 126 by RCM of ester 125 was reported by Nolen et al (Scheme 45) [198]. The RCM process was then used to create derivatives of cyclic β-amino acids 128 bearing a carbohydrate side chain from the precursor 127 (Scheme 46) [199].…”