Mechanical reconfiguration of stereoisomers.
Poly(methyl acrylate) of varying molecular weight was grown from the enantiopure ditopic initiator (R)- or (S)-1,1'-binaphthyl-2,2'-bis-(2-bromoisobutyrate). Subjecting CH(3)CN solutions of high-molecular-weight derivatives (M(N) > 25 kDa) to sonication at 0 degrees C resulted in >95% racemization after 24 h, as determined by circular dichroism; no appreciable racemization was observed in low-molecular-weight derivatives. Control experiments excluded the possibility of a thermal racemization mechanism.
Wiggins
Kelly M
KM
Department of Chemistry and Biochemistry, The University of Texas at Austin, Austin, Texas 78712, USA.
Hudnall
Todd W
TW
Shen
Qilong
Q
Kryger
Matthew J
MJ
Moore
Jeffrey S
JS
Bielawski
Christopher W
CW