Hz separation) and at 1.08 and 1.21 34.1-Hz separation) was 30% ee.35 Since the aldehyde sample had [a]MD -9.24°(c 4.5, CgHg), the rotation for the enantiomerically pure aldehyde is [a]20]) -30.8 ± Io (c 4.5, CgHg). Asymmetric hydroformylation results are summarized in Table II.
The ortho bis(aryne) equivalent 4,5-dibromo-3,6-diiodo-o-xylene (1) reacts with n-butyllithium in the presence of furans or N-substituted pyrroles to give diadducts. Removal of the oxygen or nitrogen bridges gives phenanthrenes. The method is applied to the synthesis of 9,10-dimethylphenanthrene (4), 1,4,5,8,9,10-hexamethylphenanthrene (7), and decamethylphenanthrene (11). The latter two compounds tautomerize in the central ring (to give 8 and 12, respectively) on mild treatment with acid.
Die Tetrabrombenzole (I) können mit verschiedenen Dienen (II) in einem zweistufigen Prozeß zu Bis‐anellierungs‐ produkten (IV) bzw. ‐ analog ‐ (V) (z.T.
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