4
848
K. Sung, C.-C. Chen / Tetrahedron Letters 42 (2001) 4845–4848
protonated isocyano carbon. However, acid-catalyzed
hydration of ketenes, which have electron-rich C and
b
O and electron-deficient C , involves slow, rate-deter-
a
10b
mining C -protonation.
b
Acknowledgements
Financial support from the National Science Council of
Taiwan, ROC (NSC 89-2113-M-006-020) is gratefully
acknowledged.
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10a
.