Rigid Dipeptide Mimetics. Stereocontrolled Synthesis of All Eight Stereoisomers of 2-Oxo-3-( N -Cbz-amino)-1-azabicyclo[4.3.0]nonane-9-carboxylic Acid Ester

The conformational properties of α,β‐dehydroamino acids with a C‐terminal ester group

“…This is consistent with the theoretical calculations performed in a water‐mimicking environment for the ΔVal residue. The ( Z )‐ΔAbu analogues also adopt the conformations α and β41, 44, 46–49, 51, 52, 54, 56, 57, 59. Only one ( E )‐ΔAbu analogue was found having a cyanide group in the side chain.…”

Design, synthesis, and application of azabicyclo[X.Y.0]alkanone amino acids as constrained dipeptide surrogates and peptide mimics

“…Alternative strategies for synthesizing indolizidin‐2‐one amino esters have involved annulation of pyroglutamic acid and proline (Schemes ) 9, 25, 26. Such routes begin by the synthesis of a suitably protected 5‐substituted proline.…”

“…Cis ‐Aldehyde (5 R )‐ 52 was then obtained by ozonolysis of olefin (5 R )‐ 51 8 . Trans ‐aldehyde (5 S )‐ 54 was made by reduction of N ‐(Boc)pyroglutamate 50b , Horner–Wadsworth–Emmons olefination on the hemiacetal, methyl ester reduction, and alcohol oxidation with Dess–Martin reagent (Scheme ) 25…”

“…Alternatively, dehydro amino esters were synthesized by treating aldehydes (5 R )‐ 52 and (5 S )‐ 54 with glycine‐derived phosphonate 6 (Scheme ) 9, 25. Indolizidin‐2‐one amino esters 39 and 57 were synthesized respectively in four and three steps by olefin hydrogenation, protecting group shuffle, and lactam cyclization.…”

A New Diastereoselective Synthetic Approach to the Enantiopure Peptidomimetic Scaffold 2‐Oxo‐1‐azabicyclo[4.4.0]decane

“…[3][4][5][6][7] Most of the syntheses described in the literature have aimed at the preparation of the 5,6-fused [8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24] and 5,7-fused [8,9,19,[24][25][26][27][28][29][30][31][32] systems ( Figure 1). Other research groups have focused on the 5,5-fused type, [19][20][21][22][23][24][25][26][27][28][29][30][31][32][33] while the 6,6-fused system has remained seldom explored. To the best of our knowledge, only one synthesis of an azabicyclo[4.4.0]decane dipeptide has been reported by Gosselin and Lubell.…”