Dendritic styryl TADDOLs as novel polymer cross‐linkers: First application in an enantioselective Et 2 Zn addition mediated by a polymer‐incorporated titanate. Preliminary communication

TADDOLs (α,α,α′,α′,‐tetraaryl‐1,3‐dioxolane‐4,5‐dimethanols) with dendritic branches attached to the aryl groups and with 8 or 16 peripheral styryl double bonds have been synthesized ( 4 and 5 ). With these compounds, dendritic molecules were employed for the first time as cross‐linkers in a polymerization. The resulting polystyrene was loaded with titanate (Ti(OCHMe 2 ) 4 ) to generate polymer beads incorporating Ti‐TADDOLate centers ( Figs. 1 and 2 ) for enantioselective catalysis (Et 2 Zn addition to PhCHO). Compared with conventionally polymer‐attached, insoluble Ti‐TADDOLates ( cf. 3 ), the new materials have a much higher catalytic activity, rather close to that of soluble analogs ( Fig. 3 ).