Stabil Ity of Cyclic Disulfides and Cyclic Dimeric Bis (disulfides) Characterization and Janette Houk and George

Introduction A s o a r t o f a q t r r d w n f t h e r e l a t i o n b e t w e e n s t r u c t u r e a n J p r o p e r t i e s o f t h e d i s u l f i d e s f o r m e d b y o x i d a t i o n o f t h i o l s u s i n g t h r o l d i s , r l f i o e i n t e r c h a n g e r e a c t i o n s , l 3 w e h a v e b e e n i n t e r e s t e d i n t h e d i s t r i b u t i o n o f p r o d u c t s o b t a i n e d f r o m o r g a n i c d i t h i o l s a m o n g m o n o m e r i c d i s u l f i d e s , c y c l i c b i s ( d i s u l f i d e s ) , a n d o l i g o r n e r i c a n d h i g h n o l e c u l a r w e i g h t d i s u l f j d e c o n t a i n i n g s p e c i e s ( e q 1 ) . T h e q u e s t i o n o f c e n t r a l m e c h a n i s t i c i n t e r e s t i n R'SSR' -<:: + '<! R'SH s-s R R S-S fsns{ ( 1 ) t h i s work concerns the fac to rs requ i red to favo r fo rmat ion o f the cyc l r c b i s ( d i s u t f i d e ) : i n p a r t i c u l a r , w h a t s t r u c t u r e s f o r t h e g r o u p R f a v o r b i s (d rsu l f i de ) a t t he rmodynarn ic equ i l i b r i r rm? A l though i t i s s t ra igh t fo rward to spec i f y s t ruc tu raL c lasses tha t genera te monomer i c d i su l f i des o r po lymer i c d i su l f i des on ox ida t ion , i den t i f y ing the s t ruc tu ra l f ea tu res requ i red to favo r cyc l i c b i s (d i su l f i des ) has p roved to be d i f f i cu l t . The rna jo r p rob lem seems to be a consistent ly unfavorable enthalpy of format ion of the cycl ic b i s (d i su l f i de ) re la t i ve to po lymer , p robab ly o r ig ina t ing in CSSC ang le s t r a i n . We and others have reported the forrnat ion of cycl ic b is (d isul f ides) and re la ted d i sc re te t r i s and te t rak i s (d i su l f i des ) under a nu rnber o f condi t ions, but the guest ion of whether these substances represent k inet ic or therrnodynamic products has not been systernat ical ly addressed. This paper desc r ibes the p repara t ion o f severa l cyc l i c b i s and t r i s (d i su l f i des ) under