1P11: i) Intramolecular aldol cyclization of L-lyxo-Hexos-5-ulose Derivatives

 G. Catelani et al.⁴¹ synthesized a new diastereoselective D-chiro-Inositol because of their biological intrest.⁴² The DBU-promoted intramolecular aldol condensation of two partially protected l-lyxo-hexos-5-ulose derivatives (39 and 40), in turn obtained starting from methyl β-D-galactopyranoside, takes place with fairly good yield and complete diastereoselectivity to give 2L-(2,3,6/4,5)-pentahydroxycyclohexanone derivatives (41 and 42). The stereoselective reduction of 41 and 41 with sodium triacetoxyborohydride leads, after catalytic debenzylation, to 47, while the sodium borohydride reduction⁴³ furnishes, with opposite stereoselectivity, a derivative of allo-inositol (48).

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41. G. Catelani, A. Corsaro, F. D’Andrea, M. Mariania, and V. Pistarà Bioorg. Med. Chem. Lett., 2002, 12, 3313.

42. M. J. Berridge, Nature, 1989, 341, 197; Billington, D. C. The Inositols Phosphates—Chemical Synthesis and Biological Significance; VCH: Weinheim, 1993.

43. P. L. Barili, G. Berti, G. Catelani, F. D’Andrea, F. De Rensis, and G. Goracci, J. Carbohydr.Chem., 1998, 17, 1167.
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