General method for synthesizing pyranoid glycals. A new route to allal and gulal derivatives.
[reaction: see text] Pyranoid glycals of all configurations can be obtained from pentoses through an olefination-cyclization-elimination sequence. The elimination can be carried out with excellent yields under radical conditions or by using common reductive reagents such as Zn/Cu, TiCl(4)/LiAlH(4), or lithium naphthalenide. The proposed method is appropriate for the synthesis of glycals with allo or gulo configurations because the cyclization step is more efficient for these substrates.
Departament de Química Analítica i Química Orgànica, Facultat de Química, Universitat Rovira i Virgili, C/Marcel.lí Domingo s/n, 43007 Tarragona, Spain.
Omar
O
Boutureira
Miguel Angel
MA
Rodríguez
M Isabel
MI
Matheu
Yolanda
Y
Díaz
Sergio
S
Castillón