A Convenient Synthesis of Versatile Side-chain Intermediates for Carbapenem Antibiotics

Preparation of (S)-N-Substituted 4-Hydroxy-pyrrolidin-2-ones by Regio- and Stereoselective Hydroxylation with Sphingomonas sp. HXN-200

“…Several methods for synthesis of optically active 4-hydroxy-pyrrolidin-2-one and its N -substituted derivatives have been developed, but each has one or more drawbacks: (1) Syntheses via direct cyclization 4c, or cyclization with ammonia or with alkyl- or aralkylamine need optically active precursors that cannot be prepared easily. (2) Preparation involving reduction of ( S )- N -benzyl-4-hydroxy-pyrrolidin-2,5-dione 9 is multistep and requires special reagents.…”

Applications of oxazolidinones as chiral auxiliaries in the asymmetric alkylation reaction applied to total synthesis

“…The chiral auxiliary 115 was then removed using LiOH-H 2 O 2 resulting in the generation of an acid 139. 120 Finally, the desired D-amino acid 136 was obtained as its HCl salt. Remarkably, while L-phenylalanine-based oxazolidinone 137 affords D-amino acids, as claimed, its D-isomer could be Scheme 29 Scheme 30 similarly employed to obtain the corresponding L-amino acids (Scheme 31).…”

A Convenient Synthesis of Chiral β3‐Amino Acids.

“…8 Removal of the chiral auxiliary 9 using LiOH-H 2 O 2 led to the formation of an acid 3 7 that was transformed into its amide 4 in the next step by the mixed anhydride method. 10 Treatment of 3 with ethyl chloroformate in the presence of Et 3 N gave an intermediate mixed anhydride, which was treated in situ with NH 4 OH to provide amide Scheme 1 Synthesis of b 3 -amino acids. Reagents and conditions: (i) NaHMDS (1.5 equiv), THF, -78 °C, 1 h; followed by allyl bromide (4.0 equiv), -78 °C to r.t., 1 h; then 45 °C, 4 h (65% for 1a, 73% for 1b, 60% for 1c, 71% for 1d, 70% for 1e).…”