6614
The above experiments illustrate that 2-(hydroxydimethylsilyl)phenyliodonium tri¯ate 3
generates benzyne 1 with a high eciency under mild conditions. In addition, the present benzyne
precursor 3 has a preferable procedure of the synthesis compared with the previously reported
2-(trimethylsilyl)phenyliodonium tri¯ate.3
In conclusion, we have developed a new approach to an excellent benzyne precursor. A new
benzyne precursor, 2-(hydroxydimethylsilyl)phenyliodonium tri¯ate 3, is readily prepared via the
bisdimethylsilylation of 1,2-dibromobenzene followed by the hydrolysis to benzoxadisilole 2 and
the phenyliodination. This procedure avoids the use of carcinogenic HMPA and the severe
reaction conditions required in the synthesis of [2-(trimethylsilyl)phenyl](phenyl)iodonium
tri¯ate. The new benzyne precursor 3 gives benzyne adducts in high yields in the reaction with
Bu4NF in the presence of trapping agents under very mild conditions.
Acknowledgements
We thank the Ministry of Education, Science, Sports and Culture, Japan, for ®nancial support
(Grants-in-Aid for Scienti®c Research).
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1
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