Threefold condensation of the sialyl Lewisx amine derivative 1 with cyclopeptides leads to multivalent glycopeptides with repetitive saccharide units. A trivalent sialyl Lewisx N‐glycopeptide proved to be a potent antagonist of E‐selectin.

only deviate slightly from the C,AIOAIC, plane; each hydrogen atom projects into the space between the two trimethylsilyl groups of the neighboring carbon atom.The fast rotation about the AI-C bond in solution results in only one N M R signal for the methyl and methine groups. These signals remain virtually unchanged on cooling a solution of 2 in toluene to -80 ' C . The methine protons of 2 (6 = -0.54) resonate far upfield from the corresponding protons in the starting material 1 (6 = 0.36), and lie in the range between the values of threefold (6 = -0.20 to -0.45) and fourfold (6 < -0.55) coordinated bis(trimethy1silyl)methylaluminum compounds.[201 The resonance of the C atom bonded to Al (6 = 9.0) also lies at a higher field than that in compounds with Al atoms having threefold coordination (R,AI-S-AIR,:[51 6 = 16.6; R,AI-Te-AIR,:['] 6 = 17.3); this corresponds to an increase of the charge density on the Al atoms. In analogy to the situation in organoboron compounds (Me,BOR or Me,BNR,),[2t1 these data possibly verify the participation of a mesomeric structure with A I L 0 II interactions between the lone pairs of electrons on oxygen and the empty p orbitals on Al."61 Esperimen tal Procedure I (1 2 4 g. 1.8 mmol) was dissolved under argon in ti-hexane (50 mL. freshly distilled over butyllithiuin) and treated with diinethyt sulfoxide (0.127 mL. 1.8 mmol. distilled over BaO) at room temperature with vigorous stirring. After about 30 min the solution had completely decolorized. The volume of the solution was reduced by half (in viicuo) and the optimal amount of isobutyllithium added (experimentally predetermined: here. 0.84 m L (0.72 mmol) of a 0 . 8 5 7~ solution in n-pentnne). Colorless crystals of 2 were obtained on cooling to -50°C. Yield: 0.95 g (75%). M.p. (under Ar): 173 C: M ,

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An effective new sialylation method is applied for the first time in an efficient synthesis of the sialyl Lewisx derivative 1. This type of compound is expected to contribute to the development of new anti‐inflammatory drugs.

The regioselective sulfation of a Lex-trisaccharide having free hydroxyl groups in 2-, 3and 4position of the galactose elucidated their different reactivities and gave mono-and disulfated Lex derivatives. P h 2 H~O ( C H , ) 6 N H C 0 2 B n NHAc