Fast and convenient divergent synthesis of aliphatic ester dendrimers by anhydride coupling.
A novel divergent approach was developed for the synthesis of dendritic aliphatic polyester structures using an acetal-protected anhydride derivative of 2,2-bis(hydroxymethyl)propionic acid as the acylating agent. This divergent synthesis is remarkable, because unlike all others, it only requires a small excess of reagent to achieve quantitative growth, and it requires no means of purification other than a simple solvent extraction or precipitation. A monodisperse sixth generation dendrimer with molecular weight of 30 711 Dalton and 192 masked hydroxyl groups was prepared in high yield and purity using 1,1,1-tris(hydroxyphenyl)ethane as the core molecule. Linear and star-shaped poly(ethylene glycol) (PEG) derivatives of narrow polydispersity were also used as core molecules in the divergent synthesis of dendritic-linear copolymer hybrids up to the fourth generation without requiring any chromatographic purification.
Ihre
H
H
Center for New Directions in Organic Synthesis, Department of Chemistry, University of California, Berkeley, CA 94720-1460, USA.
Padilla De Jesús
O L
OL
Fréchet
J M
JM