Anhydrosugars
2.4
277
⊡ Scheme 5
⊡ Scheme 6
⊡ Scheme 7
Opening of the three-membered ring in 13 with various nucleophiles provides the corresponding mono- (14; at the C-2 position) and di-substituted (15 at the C-2 and C-4 positions) derivatives ( > Scheme 6) [3].
However, when organocuprate is used as a nucleophile, another product is formed. Instead
of opening the oxirane ring, cuprate acts as a base which abstracts a proton from the C-2
2.4
277
⊡ Scheme 5
⊡ Scheme 6
⊡ Scheme 7
Opening of the three-membered ring in 13 with various nucleophiles provides the corresponding mono- (14; at the C-2 position) and di-substituted (15 at the C-2 and C-4 positions) derivatives ( > Scheme 6) [3].
However, when organocuprate is used as a nucleophile, another product is formed. Instead
of opening the oxirane ring, cuprate acts as a base which abstracts a proton from the C-2