Regio- and Stereoselective Nickel-Catalyzed Homoallylation of Aldehydes with 1,3-Dienes

Autor:	Masanari Kimura, Keisuke Iwata, Masahiko Mori, Akihiro Ezoe, Yoshinao Tamaru
Rok vydání:	2006
Předmět:	Chemistry Hydride Triethylborane Regioselectivity General Medicine General Chemistry Diethylzinc Biochemistry Catalysis Benzaldehyde chemistry.chemical_compound Colloid and Surface Chemistry Organic chemistry Stereoselectivity Aliphatic compound Isoprene
Zdroj:	Journal of the American Chemical Society. 128:8559-8568
ISSN:	1520-5126 0002-7863
DOI:	10.1021/ja0608904
Popis:	Ni(acac)(2) catalyzes homoallylation of aldehydes with 1,3-dienes in the presence of triethylborane. Triethylborane serves as a reducing agent delivering a formal hydride to the C2 position of 1,3-dienes, thus generating a formal homoallyl anion species and enabling the novel homoallylation of aldehydes. The reaction proceeds smoothly at room temperature in the absence of any phosphane or nitrogen ligands and is highly regioselective and stereoselective for a wide variety combination of aldehydes and 1,3-dienes: e.g., isoprene and benzaldehyde combine to give a mixture of anti- and syn-1-phenyl-3-methyl-4-penten-1-ol (2.2) in a ratio of 15:1 in 90% yield. Under the conditions, sterically congested aliphatic aldehydes and ketones show low yields. In such cases, diethylzinc serves as a substitute for triethylborane and yields the expected products in good yields with similarly high regio- and stereoselectivity. 1,3-Cyclohexadiene is one exception among 24 kinds of dienes examined and undergoes allylation (not homoallylation) selectively.
Databáze:	OpenAIRE
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