A new, economical, practical and racemization-free method for the reductive removal of 2-oxazolidinones from N-acyloxazolidinones with sodium borohydride

Synthesis of enantiomerically pure isotopomers of 2‐phenylpropionic acids

“…) We next turned our attention towards the synthesis of enantiomerically pure isotopomers of 2-phenylpropionic acids (R)-1, (R)-[ For these isotopomers, we chose to use Evans' well known and predictable alkylation methodology [32][33][34] as the corresponding racemic acids were not commercially available. For this particular strategy, we were required to synthesize the phenylacetylated oxazolidinone (R,S)-5, 19,20,35,36 which was achieved efficiently in 86% yield through simple deprotonation of the parent oxazolidinone (R,S)-2 (using n-BuLi in THF at À788C), followed by the slow addition of phenylacetyl chloride in THF (Scheme 2). With this substrate in-hand, we next focused our attention on its diastereoselective methylation using Evans' well known deprotonation-alkylation [32][33][34] 21 was shown to be configurationally stable under the resolution conditions (Scheme 4).…”

Synthesis of14C-labeled and tritiated AMPA potentiator LY450108

“…Therefore the nitro compound 4 was used in the preparation of the target molecule LY450108. After an unsuccessful attempt of direct transamination of the oxazolidinone 4 with ammonium chloride and trimethylaluminum, 7 the reductive removal of the chiral auxiliary was accomplished using sodium borohydride 8 to give the primary alcohol 10 in a good yield. Conversion of 10 to the corresponding primary amine 13 was performed in two alternative ways.…”

Total Synthesis of Structurally Complex Marine Oxacyclic Natural Products

“…The synthesis of the AB-ring enol phosphate 94 started with Evans asymmetric aldol reaction 61 of aldehyde 96 with oxazolidinone 97, which was followed by reductive removal of the chiral auxiliary 62 to deliver 1,3-diol 98 as a single diastereomer (Figure 12). This was converted to allylic alcohol 99 by a Figure 11.…”

“…A two-stage oxidation followed by condensation with (S)-4-benzyl-2-oxazolidinone (149) 85 afforded imide 150, whose asymmetric alkylation under Evans conditions 86 led to methylated product 151 as a single stereoisomer. After reductive removal of the chiral auxiliary, 62 iodination of the derived alcohol 152 furnished iodide 141.…”