1,3-Oxazin-2-ones vs tetrahydrofurans by iodocyclisation of 2-alkoxycarbonylamino-3-alken-1-ols
Iodocyclisation of primary homoallylic alcohols 2a– d, containing either a 2- t-butoxy- or a benzyloxycarbonylamino group, was studied, in order to establish the nucleophilic group involved in cyclofunctionalisation. In fact, the N- t-Boc derivative 2a gave the oxazinone 3, exclusively, whereas star...
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Published in | Tetrahedron: asymmetry Vol. 11; no. 18; pp. 3769 - 3777 |
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Main Authors | , , , , , |
Format | Journal Article |
Language | English |
Published |
OXFORD
Elsevier Ltd
22.09.2000
Elsevier |
Subjects | |
Online Access | Get full text |
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Summary: | Iodocyclisation of primary homoallylic alcohols
2a–
d, containing either a 2-
t-butoxy- or a benzyloxycarbonylamino group, was studied, in order to establish the nucleophilic group involved in cyclofunctionalisation. In fact, the
N-
t-Boc derivative
2a gave the oxazinone
3, exclusively, whereas starting from the
N-Cbz derivative
2b a diastereomeric mixture of substituted tetrahydrofurans
4 and
5 resulted in ratios depending upon the reaction conditions. These results were rationalised by means of computational methods. On the contrary, migration of both the
t-butyl or benzyl group to the hydroxy group was observed when both
2c and
2d underwent cyclisation to give the corresponding 5-alkoxymethyl oxazolidin-2-ones
7a,
b in low yield, but with high regio- and stereocontrol. |
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ISSN: | 0957-4166 1362-511X |
DOI: | 10.1016/S0957-4166(00)00323-2 |