Ring‐Closure Reactions through Intramolecular Displacement of the Phenylselenonyl Group by Nitrogen Nucleophiles: A New Stereospecific Synthesis of N‐Tosyl and N‐Benzoyl‐1,3‐oxazolidin‐2‐ones from β‐Hydroxyalkyl Phenyl Selenides

Abstract

A new and convenient method for the stereospecific synthesis of variously substituted 1,3-oxazolidin-2-ones from the easily available beta-hydroxyalkyl phenyl selenides is presented. After transformation into the N-tosyl or N-benzoyl carbamates, the selenides were oxidized to the corresponding selenones. The key step of the process is the ring-closure reaction, which occurs by stereospecific intramolecular nucleophilic substitution of the selenone group by the nitrogen atom of the carbamate. Enantiomerically pure 1,3-oxazolidin-2-one derivatives can be easily prepared by using enantiomerically pure beta-hydroxyalkyl phenyl selenides as starting materials.

Magnesium bis(monoperoxyphthalate) hexahydrate as mild and efficient oxidant for the synthesis of selenones

“…The N -substituted-1,3-oxazolidin-2-ones 3h and 3i were obtained in 94% and 82% yields respectively as a result of the intramolecular displacement of the phenylselenonyl group by the nitrogen atom of the carbamic group. These results are in accordance with precedent oxidation–cyclization reactions performed with MCPBA (96% and 88% respectively) [11]. The presence of the phenylselenone intermediate in the above reactions was already and unambiguously demonstrated [11].…”

“…These results are in accordance with precedent oxidation–cyclization reactions performed with MCPBA (96% and 88% respectively) [11]. The presence of the phenylselenone intermediate in the above reactions was already and unambiguously demonstrated [11]. On the other hand, the oxidation of 1d with MMPP in ethanol allowed to isolate and to fully characterize (high resolution mass spectra and NMR analysis) the expected selenone intermediate 2d (Table 1, entry 4).…”

“…Similarly the dihydrooxazine 3g [14] was easily obtained in good yield by the oxidative cyclization of the acylamino phenyl selenide 1g with MMPP in methanol (Table 2, entry 4) although in lower yield than reported before (90% [14]). As reported in Table 2 (entries 5 and 6), the N -tosyl-1,3-oxazolidin-2-one [11] 3h and the N -benzoyl-1,3-oxazolidin-2-one [11] 3i were easily obtained by MMPP oxidation of the corresponding β-carbamoyloxyalkyl phenyl selenides 1h and 1i in tetrahydrofuran. The N -substituted-1,3-oxazolidin-2-ones 3h and 3i were obtained in 94% and 82% yields respectively as a result of the intramolecular displacement of the phenylselenonyl group by the nitrogen atom of the carbamic group.…”

“…A wide range of heterocyclic compounds can be obtained by intramolecular nucleophilic substitution reactions e.g. epoxides from β-hydroxy phenyl selenides [9–10], N -benzoyl- and N - tosyl-1,3-oxazolidin-2-ones from β-hydroxyalkyl phenyl selenides [11], N -arenesulfonylazetidines from γ-(phenylseleno)alkyl arylsulfonamides [12], N -acylaziridines [13], 1,3-oxazolines, dihydrooxazine and pyrrolidines from acylamino phenyl selenides [14]. Interestingly, the intramolecular substitution reaction of a phenylselenonyl group was used on enantioenriched γ-hydroxyalkyl phenyl selenides to obtain optically active 2-substituted tetrahydrofurans [15] (see Scheme 2).…”

Catalytic Enantioselective Ring-Opening Reaction of meso-Epoxides with ArSeH Using a (Salen)Ti(IV) Complex

“…Chiral organoselenium compounds have been employed as useful ligands, catalysts, or intermediates in various asymmetric transformations such as diethylzinc addition to aldehydes, asymmetric hydrosilylation, and 1,4-addition of Grignard reagents to enones [11][12][13]. Tiecco et al recently described mild and convenient methods for the synthesis of enantiomerically pure substituted 1,3-oxazolidin-2-ones and tetrahydrofurans starting from chiral 1,2-arylseleno alcohols [14,15]. It is of interest to obtain the optically active 1,2-arylseleno alcohols by the catalytic asymmetric desymmetrization of meso-epoxides with selenols.…”