M. Tingoli et al., The reactivity of furanoid and pyranoid glycals towards aromatic Grignard reagents and a nickel catalyst, TETRAHEDR L, 40(52), 1999, pp. 9329-9332
By reaction with aromatic Grignard reagents in the presence of low valent n
ickel species at low temperature, the 1,2-unsaturated furanoid glycal (1) u
ndergoes coupling reaction to produce 2,3-unsaturated products (1a,b) as pu
re stereoisomers. When these reaction conditions are applied to protected 1
,2-unsaturated pyranoid glycals (2, 3, 4), both cross-coupling and eliminat
ion reactions occur to give conjugated diene-alcohol derivatives (2a; 3a,b;
4a,b, respectively), in moderate yield. (C) 1999 Elsevier Science Ltd. All
rights reserved.