C–C Bond Formation
2.5
331
⊡ Scheme 47
⊡ Scheme 48
⊡ Scheme 49
ly gave desired 183, together with considerable 4-deoxy byproduct due to 1,3-diaxial repulsion between iodide and the C 2 -benzoate ( > Scheme 49). When thionocarbamate 182 was
subjected to allyltributyltin and dilauoryl peroxide in refluxing benzene, only the equatorially C 4 -allylated methyl 2,3,6-tri-O-benzoyl-4-deoxy-4-C-allyl-D-mannopyranoside 183 was
2.5
331
⊡ Scheme 47
⊡ Scheme 48
⊡ Scheme 49
ly gave desired 183, together with considerable 4-deoxy byproduct due to 1,3-diaxial repulsion between iodide and the C 2 -benzoate ( > Scheme 49). When thionocarbamate 182 was
subjected to allyltributyltin and dilauoryl peroxide in refluxing benzene, only the equatorially C 4 -allylated methyl 2,3,6-tri-O-benzoyl-4-deoxy-4-C-allyl-D-mannopyranoside 183 was