CHIRAL TRIOLS OF C3-SYMMETRY: SYNTHESIS AND APPLICATION TO CHIRAL RECOGNITION

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We have devised new asymmetric boron-mediated double aldol reactions complementarily useful for the synthesis of aliphatic and aromatic substituted chiral triols of C3-symmetry, which are potential precursors for the study of asymmetric catalysis and chiral recognition, via double aldol reactions of a chiral acetate ester or a chiral acetyloxazolidinone.Chiral dendrimenrs having a chiral triol of C3-symmetry as a core element with 3, 5-disubstituted benzyl ether type dendrone of the 3^<rd> to 5^<th> generation were synthesized. The chiroptical properties of these dendrimers were examined and shown to exibhit the "dilution effect", eveidence of their of "molecular chirality being not observed.Tris-pyridine, and tris-bipyridine substituted compounds were synthesized to examine properties of their metal complexes. Tris-2-pyridylmethyl and tris-3-pyridylmethl substituted chiral triols were synthesized. Their copper complexes were shown to be 1: 1, and 2: 1 complex, respectively, by ESI-MS measurement. Catalytic of these complexes was examined.Tris-6'-methyl-6-(2, 2 -bipyridylmethyl) substituted triols did not afford Ru complex upon treatment with 5'-methyl-5-chloromethy-2, 2'bipyridine proceeded only low yield (<10%). An alternate route using Stille coupling of stannylpyridine and 2-bromopyridylmethyl substituted chiral triols will be executed.