3126
In summary, chiral dendrimers 1a (G1) and 1b (G2) with rigid hydrocarbon backbones are useful
catalysts for the enantioselective addition of dialkylzincs. Application of these chiral dendrimers to other
asymmetric syntheses is in progress.
Acknowledgements
We thank Professors James D. Wuest at the Université de Montréal and Peter J. Stang at the University
of Utah for information on the preparation of compound 5 and ethynylbenzene, respectively. Partial
financial support from the Ministry of Education, Science, Sports and Culture, Japan is gratefully
acknowledged.
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9. Data of 1a (G1): [α]D26 +3.8 (c 1.0, MeOH); 1H NMR (300 MHz, CDCl3) δ 1.02 (9H, d, J=6.8 Hz), 2.20 (9H, s), 2.70 (3H,
br s), 2.92 (3H, qd, J=6.8, 5.0 Hz), 3.64 (6H, s), 4.86 (3H, d, J=5.0Hz), 7.2–7.5 (27H, m), 7.64 (3H, s); 13C NMR (75 MHz,
CDCl3) ppm 10.2, 39.1, 59.3, 64.0, 74.3, 88.1, 90.9, 121.8, 124.5, 126.6, 127.5, 128.5, 129.1, 132.1, 134.3, 140.7, 142.9; IR
(KBr) 3379, 2208 cm−1; HR MS (FAB+) found m/z 910.4937, calcd for C63H64N3O3 (M+1): 910.4949.
25
1
10. Data of 1b (G2): [α]D −34.1 (c 1.4, CHCl3); H NMR (300 MHz, CD2Cl2) δ 1.01 (18H, d, J=6.8 Hz), 2.21 (18H, s),
2.60 (6H, br s), 2.91 (6H, qd, J=6.8, 5.0 Hz), 3.63 (12H, s), 4.86 (6H, d, J=5.1 Hz), 7.2–7.7 (66H, m); 13C NMR (125
MHz, CD2Cl2) ppm 9.8, 38.7, 59.1, 64.1, 74.4, 87.6, 88.6, 89.5, 90.9, 121.5, 123.9, 124.2, 124.7, 126.6, 127.4, 128.3, 129.1,
132.0, 134.3, 134.8, 141.1, 143.4; IR (KBr) 3429, 2210 cm−1; HR MS (FAB+) found m/z 2041.029, calcd for C144H132N6O6:
2041.021.
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