2003 Amines

200348.fm Page 85 Friday, October 31, 2003 2:17 PM

AminesQ 0120 A New Chiral Masked Form of Glyoxal Diimine. — Controlled (stepwise) addition

of organolithium reagents to diamine (I), the chiral masked form of glyoxal diimine, leads to rearrangement and/or substitution reactions of one or two branched allyl groups affording C1-symmetric 1,2-diamines (III), C2-symmetric 1,2-diamines (VI), and C1-symmetric 1,2-disubstituted 1,2-diamines (VIII) with good diastereoselectivities. Although providing better diastereoselectivities than the direct double addition of or-ganolithium reagents to chiral glyoxal diimine, the preparation of symmetrically dis-ubstituted diamines (VI) is not advantageous by using the masked form (I). However, diene (I) is useful for the preparation of C1-symmetric unsymmetrically disubstituted diamines like (VIII), since no general method for their preparation is known. — (MARTELLI, G.; SAVOIA*, D.; Collect. Czech. Chem. Commun. 68 (2003) 8, 1531-1540; Dip. Chim. "G. Ciamician", Univ. Bologna, I-40126 Bologna, Italy; Eng.) — H. Hoennerscheid

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