Yadav, J. S.; Joshi, B. V.; Gadgil, V. R., Indian Journal of Chemistry - Section B Organic and Medicinal Chemistry, 1987, vol. 26, # 1-12, p. 399 - 400
Yadav, J. S.; Joshi, B. V.; Gadgil, V. R., Indian Journal of Chemistry - Section B Organic and Medicinal Chemistry, 1987, vol. 26, # 1-12, p. 399 - 400
A series of spiroketal C2-acetals was treated with an alkylsilane reagent in the presence of either TMSOTf or BF3.OEt2 to effect C2-substitution. Regioselective alkylation was successful, but in each case a monoanomeric spiroketal was the unexpected major product. The sequence provides a model for the synthesis of the CD subunit of altohyrtin A. (C) 1998 Elsevier Science Ltd. All rights reserved.