Conformational diastereoisomerism in a chiral pretzelane
作者:Yi Liu、Scott A. Vignon、Xiyun Zhang、K. N. Houk、J. Fraser Stoddart
DOI:10.1039/b507679j
日期:——
The introduction of a stereogenic center by a stereospecific synthesis into an optically active, donor-acceptor pretzelane, that exhibits helicity as well as fixed chirality, leads to a marked preference for one conformationaldiastereoisomer over the other in both acetone and dimethylsulfoxide that can be understood from computational models.
作者:Y. Liu、S. A. Vignon、X. Zhang、P. A. Bonvallet、S. I. Khan、K. N. Houk、J. F. Stoddart
DOI:10.1021/jo051430g
日期:2005.11.1
A series of donor-acceptor pretzelanes has been synthesized, using self-assembly and template-directed protocols, and the dynamic processes that these pretzelanes undergo have been investigated in solution. These compounds exist as libraries of diastereoisomers as a result of their multiple stereoelements, which are dynamically interconverted by several different, in some cases competing, processes. Altering the structure of the pretzelanes changes the rates and mechanisms by which these diastereoisomers equilibrate. Additionally, inserting an element of fixed chirality allows the equilibrium to be biased, while maintaining the barrier to the equilibration processes. These results bode well for the future construction of molecular devices based on switchable diastereoisomerism involving metastable states.