title: Water-soluble cavitands promote hydrolyses of long-chain diesters.
abstract: Water-soluble, deep cavitands serve as chaperones of long-chain diesters for their selective hydrolysis in aqueous solution. The cavitands bind the diesters in rapidly exchanging, folded J-shape conformations that bury the hydrocarbon chain and expose each ester group in turn to the aqueous medium. The acid hydrolyses in the presence of the cavitand result in enhanced yields of monoacid monoester products. Product distributions indicate a two- to fourfold relative decrease in the hydrolysis rate constant of the second ester caused by the confined space in the cavitand. The rate constant for the first acid hydrolysis step is enhanced approximately 10-fold in the presence of the cavitand, compared with control reactions of the molecules in bulk solution. Hydrolysis under basic conditions (saponification) with the cavitand gave >90% yields of the corresponding monoesters. Under basic conditions the cavitand complex of the monoanion precipitates from solution and prevents further reaction.
authors.affiliation: Department of Chemistry, Fudan University, Shanghai 200433, China;
authors.forename: Qixun
authors.initials: Q
authors.lastname: Shi
authors.affiliation: Department of Chemistry, The Scripps Research Institute, La Jolla, CA 92037;
authors.forename: Matthew P
authors.initials: MP
authors.lastname: Mower
authors.affiliation: Department of Chemistry, The Scripps Research Institute, La Jolla, CA 92037; blackmond@scripps.edu jrebek@scripps.edu.
authors.forename: Donna G
authors.initials: DG
authors.lastname: Blackmond
authors.affiliation: Department of Chemistry, Fudan University, Shanghai 200433, China; Department of Chemistry, The Scripps Research Institute, La Jolla, CA 92037; The Skaggs Institute for Chemical Biology, The Scripps Research Institute, La Jolla, CA 92037 blackmond@scripps.edu jrebek@scripps.edu.
authors.forename: Julius
authors.initials: J
authors.lastname: Rebek
keywords: cavitands; chemical selectivity; supramolecular chemistry