Methods of Non-a-Amino Acid Synthesis, 2nd Edition

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Methods of Non-α-Amino Acid Synthesis, Second Edition

Other hydroxy amino acid derivatives can be prepared by a [3+2]-cycloaddition

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route, and there are other methods that generate nitrones. Nitro compounds react

with alkenes, in the presence of isocyanates, to produce dihydroisoxazole deriva-

tives via a nitrile N-oxide.

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Kametani and coworkers generated nitrile N-oxide 99

in situ from the reaction of nitro compound 98 and phenylisocyanate. When 99 was

condensed with tert-butylcrotonate, 100 was formed in 58% yield, along with 14% of

101.

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Isolation of 100 was followed by catalytic hydrogenation to give a 1:1 mixture

of 102 and 103. Isocyanates ...