Stereoselective Synthesis of 2,3,4-Trisubstituted Tetrahydrofurans.-Treatment of the protected α-alkyl hydroxyaldehydes (I) and (IV) with the diazoacetates (II) in the presence of a Lewis acid forms the corresponding trisubstituted tetrahydrofurans stereoselectively. In general, triethylsilyl-protected derivatives (IV) afford higher yields of the tetrahydrofuran product. In addition, stereoselectivity increases with steric bulk of the α-alkyl substituent.-(ANGLE, S. R.; BERNIER, D. S.; CHANN, K.; JONES, D. E.; KIM, M.; NEITZEL, M. L.; WHITE, S. L.; Tetrahedron Lett. 39 (1998) 45, 8195-8198; Dep. Chem., Univ. Calif., Riverside, CA 92521, USA; EN)
Synthesis of Tetrahydrofurans from Protected β-Hydroxyaldehydes:Optimization of the Alcohol Protecting Group.-The conversion of silyl-protected β-hydroxyaldehydes (I) to tetrahydrofurans (III) by reaction with the diazoester (II) is investigated. Low yields of the desired tetrahydrofuran are obtained with aldehyde (Ic), while other protecting groups afford good to fair yields. -(ANGLE, S. R.; BERNIER, D. S.; EL-SAID, N. A.; JONES, D. E.; SHAW, S. Z.; Tetrahedron Lett. 39 (1998) 23, 3919-3922; Dep. Chem., Univ.
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