Forty-six-and fifty-membered endo-functionalized macrocycles were obtained by template syntheses with new stiff tetracyclic tetraols 10 and 11. Reaction of dialkenylated boronic acids 1 with template molecules 10 and 11 generated preorganized bisboronic esters 18 and 19, which were cyclized by ring-closing olefin metathesis. Resulting bimacrocycles 20 and 21 were obtained in ca. 60 % yield when alkenyl chains of sufficient lengths were used. The E/E, E/Z, and Z/Z mixtures were hydrogenated to give saturated bimacro-

2,6-Bis(alkenyloxy) substituted arylboronic acids can be cyclotrimerized with the help of a hexaol as a template. First, the boronic acids are assembled by boronic ester formation with hexahydroxy-bicyclo[2.2.2]octane. Next, the resulting triboronates are cyclized by ring-closing metathesis to yield trimacrocycles as diastereomeric E/Z mixtures. Catalytic hydrogenation yields a single saturated trimacrocycle. Cleavage of the boronic ester functions liberates the template and generates a macrocycle with three boronic acid functionalities in endo-orientation. Due to this preorganization, macrocycles with boronic acids in endo-positions are good receptors for polyols. The binding of carbohydrates such as fructose was compared with the uptake of the respective templates into macrocycles with two or three boronic acids in endo-orientation.

Several stiff tetraols can be used as templates for the synthesis of bimacrocyclic diboronic esters. The endo-boronic acid functionalities can be substituted to give new endo-functionalized macrocycles (phenols, biphenyls) or new bimacrocycles (concave pyridines or concave 1,10-phenanthrolines).

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