Abstract
A (−)-menthone-derived nitrone and various allyl
O-, and
S-glycosides reacted at 110 °C to afford the corresponding cycloadducts in good yields. For an
N-acetylated allyl
N-glycoside, an
N-glycoside-based product was formed in poor yield with loss of the
N-acetyl residue, while the major product
4 (60%), in which the sugar moiety was absent, arose from cleavage of the
N-glycosidic bond, under the cycloaddition conditions. The cycloadducts of the
O-, and
S-glycoside type were ring-opened and subjected to acidic and basic hydrolysis, for removing the chiral auxiliary. This resulted in glycosidic bond cleavage for
O-glycosides and loss of material, while an
S-glycoside amino acid was isolated in 78% yield, indicating a higher resistance of the
S-glycosidic bond. N–O Bond cleavage and hydrolytic treatments applied to
4 afforded 4(
S)-4-hydroxy-
l-ornithine in high yield. Use of the nitrone derived from (+)-menthone should afford the enantiomer of
4, both precursors of 4-hydroxy arginine derivatives by guanidination.
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