Co(thd)2: a superior catalyst for aerobic epoxidation and hydroperoxysilylation of unactivated alkenes: application to the synthesis of spiro-1,2,4-trioxanes

Autor:	B. Kevin Park, Paul M. O'Neill, Dauda S. Kapu, Stephen Hindley, Paul A. Stocks, Jill Davies, Matthew D. Pugh, Patrick G. Bray, Stephen A. Ward
Rok vydání:	2003
Předmět:	chemistry.chemical_classification Total harmonic distortion Ketone Chemistry Organic Chemistry Enantioselective synthesis chemistry.chemical_element General Medicine Medicinal chemistry Biochemistry Catalysis Cyclic Alkenes Yield (chemistry) Drug Discovery Organic chemistry Cobalt
Zdroj:	Tetrahedron Letters. 44:8135-8138
ISSN:	0040-4039
DOI:	10.1016/j.tetlet.2003.09.033
Popis:	Bis(2,2;6,6-tetramethyl-3,5-heptanedionato)cobalt(II) (Co(thd)(2)), a beta-diketonate prepared in a simple one-step procedure, is an excellent catalyst for aerobic epoxidation and Mukaiyama-Isayama hydroperoxysilylation of unactivated alkenes. For hydroperoxysilylation, Co(thd)(2) is superior to Co(acac)(2) and can catalyse oxidation of cyclic alkenes in excellent yield. Chiral beta-diketonate or keto iminato catalysts failed to catalyse this reaction in an enantioselective manner and a free radical mechanism consistent with this observation is proposed. Hydroperoxysilylation of cyclohex-1-enylmethanol by Co(thd)(2) followed by addition of a ketone/TsOH provides a simple one-pot procedure for the synthesis of spiro-1,2,4-trioxane antimalarials. (C) 2003 Published by Elsevier Ltd.
Databáze:	OpenAIRE
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