Premium
Catalytic Hydrogenation of N‐protected α‐Amino Acids Using Ruthenium Complexes with Monodentate Phosphine Ligands
Author(s) -
Saito Akari,
Yoshioka Shota,
Naruto Masayuki,
Saito Susumu
Publication year - 2020
Publication title -
advanced synthesis and catalysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.541
H-Index - 155
eISSN - 1615-4169
pISSN - 1615-4150
DOI - 10.1002/adsc.201901298
Subject(s) - chemistry , denticity , phosphine , ruthenium , ligand (biochemistry) , medicinal chemistry , catalysis , alkyl , asymmetric hydrogenation , yield (engineering) , crystal structure , organic chemistry , stereochemistry , enantioselective synthesis , biochemistry , materials science , receptor , metallurgy
A ruthenium complex with a monodentate phosphine ligand was used to catalytically hydrogenate N‐protected α‐amino acids under essential retention of the configuration of their α‐chiral centers. Among the ligands tested for this hydrogenation, which proceeds at a relatively low temperature, tris( para ‐fluorophenyl)phosphine exhibited the best performance. In comparison, electron‐rich monodentate, bidentate, and tridentate phosphines were far less effective. The precatalyst Ru(OAc) 2 [( p ‐FC 6 H 4 ) 3 P] 2 was synthesized and isolated, and its structure was determined by a single‐crystal X‐ray diffraction analysis. N‐protected α‐amino acids with neutral alkyl side chains, including polar functional groups such as sulfides, indoles, ethers, phenols, pyrroles, and arenes, are compatible with the applied hydrogenation conditions, affording the corresponding optically active 2‐substituted‐2‐(1 H ‐pyrrol‐1‐yl)ethan‐1‐ol (2‐amino ethanol) derivatives in moderate to high yield.