Diastereoselective intramolecular acyl transfer of 5-(α-methylbenzyl)amino-1,3-dioxan-2-one to 4-hydroxymethyl-2-oxazolidinones

Abstract

Intramolecular acyl transfer of ( R)-5-(α-methylbenzyl)amino-1,3-dioxan-2-one ( 2) by treatment with DBU in CD 2Cl 2, CDCl 3, C 6D 6, CD 3CN, CD 3NO 2, DMSO- d 6, DMF, THF- d 8, i PrOH, and t BuOH at room temperature afforded (4 S,α R)-4-hydroxymethyl-3-α-methylbenzyl-2-oxazolidinone [(4 S)- 3] in moderate to quantitative yields with 58–94% de via an asymmetric desymmetrization process. Treatment of 2 with DBU and Cs 2CO 3 in MeOH and EtOH gave (4 S)- 3 and (4 R)- 3 without diastereoselectivities. Acidic treatment of 2 using HCO 2H, AcOH, EtCO 2H, i PrCO 2H, t BuCO 2H, and C 6F 5OH in CDCl 3 gave (4 S)- 3 in moderate diastereoselectivities (26–52% de). First-order kinetics were observed in the reaction of 2 to (4 S)- 3 with DBU in CDCl 3 and THF- d 8.