0000000000331967
AUTHOR
Maria Fomitšenko
Formation and trapping of the thermodynamically unfavoured inverted-hemicucurbit[6]uril
Amplification of a thermodynamically unfavoured macrocyclic product through the directed shift of the equilibrium between dynamic covalent chemistry library members is difficult to achieve. We show for the first time that during condensation of formaldehyde and cis-N,N'-cyclohexa-1,2-diylurea formation of inverted-cis-cyclohexanohemicucurbit[6]uril (i-cis-cycHC[6]) can be induced at the expense of thermodynamically favoured cis-cyclohexanohemicucurbit[6]uril (cis-cycHC[6]). The formation of i-cis-cycHC[6] is enhanced in low concentration of the templating chloride anion and suppressed in excess of this template. We found that reaction selectivity is governed by the solution-based template-a…
Template-controlled synthesis of chiral cyclohexylhemicucurbit[8]uril
Enantiomerically pure cyclohexylhemicucurbit[8]uril (cycHC[8]), possessing a barrel-shaped cavity, has been prepared in high yield on a gram scale from either (R,R,N,N')-cyclohex-1,2-diylurea and formaldehyde or cycHC[6]. In either case, a dynamic covalent library is first generated from which the desired cycHC can be amplified using a suitable anion template.
CCDC 1569570: Experimental Crystal Structure Determination
Related Article: Elena Prigorchenko, Sandra Kaabel, Triin Narva, Anastassia Baškir, Maria Fomitšenko, Jasper Adamson, Ivar Järving, Kari Rissanen, Toomas Tamm, Riina Aav|2019|Chem.Commun.|55|9307|doi:10.1039/C9CC04990H