Stabilizing effect of intramolecular lewis base toward racemization of optically active selenoxides

Abstract

2-(Methylchalcogenomethyl)diphenyl selenoxides 1 and 2-{2 -(N,N-dimethylamino)ethyl}

Recent Advances in Organoselenium Chemistry

“…Interestingly the reaction proceeds with retention of configuration. In further studies, Shimizu and co‐workers showed the stabilizing effect of intramolecular Lewis bases toward racemization of optically active selenoxides 113…”

Optically Active Selenoxides: Structural and Synthetic Aspects

“…A similar optical resolution ( Figure 6) was applied to racemic 2-(methylchalcogenomethyl)diphenyl selenoxides 153-154 and 2-{2_-(N, N-dimethylamino)ethyl}-phenyl alkyl (or aryl) selenoxides 156-158. However, selenoxide 155 could not be resolved by this procedure [60]. Three enantiomerically pure 8-(dimethylamino)-1-aryl(alkyl)-naphthyl selenoxides 159-161 (Figure 7) were isolated by chromatographic resolution using a chiral column ((Daicel Chiralpak AS; 10 × 250 mm).…”

“…The common features that exist between the CD spectra of selenoxides 143-149 and optically active p-tolyl mesityl sulfoxide and p-tolyl 2,4,6-triisopropylphenyl sulfoxide were used to assign the absolute configuration of the dextrarotatory selenoxide enantiomers [57,58]. The relationship between the absolute configurations around a stereogenic selenium atom of 2-(methylchalcogenomethyl)diphenyl selenoxides 153-154 and 2-{2-(N,N-dimethylamino)ethyl}-phenyl alkyl (or aryl) selenoxides 156-158 and the chiroptical properties of the enantiomers of was clarified by comparing with those of sulfur analogues [60]. Earlier, the absolute configurations of the optically active chalcogen oxides 159-161 were assigned by comparison of their specific rotations and CD spectra with those of their sulfur analog [61,62].…”

“…12, x FOR PEER REVIEW 16 of (Dimethylamino)methyl)phenyl alkyl (aryl) selenoxides 150-152 N-dimethylamino)ethyl}-phenyl alkyl (or aryl) selenoxides 156-158 . However, selenoxide 155 could not be resolved by this procedure [60]…”

Theoretical Studies of [2,3]-Sigmatropic Rearrangements of Allylic Selenoxides and Selenimides

“…As shown in the synthesis of solandelactone E ( Figure 1 b), the rearrangement tolerates a variety of functional groups. Enantioselective synthesis of chiral allylic alcohols and amines is possible when either the selenoxide is produced using a chiral oxidizing agent or a chiral ancillary group including those that stabilize the selenoxide against racemization [ 1 , 7 , 8 , 9 , 10 ].…”