Thermodynamically stabilized chiral chalcogen oxides: optical resolution and stereochemistry

Optically Active Selenoxides: Structural and Synthetic Aspects

“…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). It is interesting to note that the first eluted enantiomer of selenoxide 159 had a positive specific rotation, whereas the first eluted enantiomer of selenoxides 160-161 had a negative specific rotation [61,62]. In addition to chromatographic resolutions mentioned above, several simple aryl alkyl 85 and 162-167 and dialkyl selenoxides 168-170 ( Figure 8) were resolved into pure enantiomers via complexation with enantiomerically pure 2,2'-dihydroxy-1,1'-binaphthol 171 or 1,6-di(o-chlorophenyl)-1,6-diphenylhexa-2,4-diyne-1,6-diol 172.…”

“…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]. Similarly, the absolute configuration of dextrorotatory 2-(hydroxymethyl) phenyl methyl selenoxide (+)-177 was determined to be R by comparison of its specific rotations and CD spectra with those of that (R)-2-(hydroxymethyl) phenyl methyl sulfoxide.…”

Naphthalene and Related Systems peri‐Substituted by Group 15 and 16 Elements

“…Optical resolution was achieved by liquid chromatography using optically active columns and the chalcogen oxides were assigned by their specific rotations and CD spectra. [173] Kinetic studies indicated that intramolecular coordination of the nitrogen atom to the chalcogen atom leads to thermodynamic stabilisation and prevented racemisation. [173] NapEP Systems (E = O, S, Se, Te)…”

“…[173] Kinetic studies indicated that intramolecular coordination of the nitrogen atom to the chalcogen atom leads to thermodynamic stabilisation and prevented racemisation. [173] NapEP Systems (E = O, S, Se, Te)…”

Peptidyl Succinimidyl Peptides as Taspase 1 Inhibitors

“…The facile C–H lithiation of dimethylnaphthylamine Me 2 N–Nap ( B ) using n ‐butyllithium5 and subsequent salt metathesis with (organo)element halides proved to be a straight‐forward route for the synthesis of intramolecularly coordinating 8‐dimethylaminonaphthyl‐element species 1‐( R n E )‐8‐(Me 2 N)‐Nap ( C ) featuring the elements E = B,6,7 Al,8–12 Ga,10 In,10,13 Tl,13 Si,14–20 Sn,14,21–24 P,25–28 As,30,31 Sb,31,32 Bi,31,33 S,34–38 Se,39–41 and Te 30–48. Within these compounds, short E ··· N transannular distances are frequently observed, which are indicative of strong attractive interactions.…”