by vacuum pump then CuSO4 (0.75 mmol), Cu wire (10 mg) and
benzyl azide (0.75 mmol) were added and stirring continued at
the same temperature for 18 h. The crude reaction mixture was
worked up with aqueous NH4Cl and the aqueous layer extracted
with dichloromethane (2 × 20 mL). The combined organic layers
were dried (Na2SO4), filtered and concentrated. Pure products 12
were obtained by column chromatography (silica gel, mixture of
hexane–ethyl acetate).
M. B. Corre´a, C. A. F. de Oliveira, A. C. Pinto and R. B. de Alencastro,
J. Org. Chem., 2003, 68, 8815.
6 For a review of click-chemistry see: (a) H. C. Kolb, M. G. Finn and
K. B. Sharpless, Angew. Chem., Int. Ed., 2001, 40, 2004; (b) L. V. Lee,
M. L. Mitchell, S. J. Huang, V. V. Fokin, K. B. Sharpless and C. H.
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Many of the cascade products 7, 8, 10 and 11 are commercially
available, or have been described previously, and their analytical
data match literature values. New compounds were characterized
1
on the basis of IR, H and 13C NMR and analytical data (see
supporting information†).
Acknowledgements
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This work was made possible by a grant from The Department
of Science and Technology (DST), New Delhi and Council of
Scientific and Industrial Research (CSIR), New Delhi. GBR
thanks University Grants Commission (UGC), New Delhi for his
research fellowship. We are thankful to Professor A. Srikrishna
and his research group, Department of Organic Chemistry, IISc,
Bangalore for their help to obtain HRMS data of all reported
compounds.
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