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Dihaloindium hydride as a novel reducing agent
Author(s) -
Baba Akio,
Shibata Ikuya
Publication year - 2005
Publication title -
the chemical record
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.61
H-Index - 78
eISSN - 1528-0691
pISSN - 1527-8999
DOI - 10.1002/tcr.20055
Subject(s) - chemistry , aldol reaction , hydride , halogenation , organic chemistry , catalysis , reagent , phosphine , intramolecular force , combinatorial chemistry , medicinal chemistry , hydrogen
Dihaloindium hydrides (X 2 InH) are novel reducing reagents, which act in both an ionic and a radical manner. The hydrides were easily generated from InX 3 and Bu 3 SnH to reduce a variety of functionalities such as aldehydes, ketones, enones, and imines. The combination of a phosphine and Cl 2 InH accomplished the selective transformation from acid chlorides to aldehydes. One‐pot treatment of Cl 2 InH, enones, and aldehydes achieved reductive aldol reactions, in which the predominant reduction of enones was followed by an aldol reaction between the resulting indium enolates and the remaining aldehydes. It is noteworthy that both anti ‐ and syn ‐selective aldols were obtained by the use of THF and an aqueous solvent, respectively. The replacement of Bu 3 SnH with Et 3 SiH as a hydride source allowed the catalytic use of InBr 3 to give the syn ‐selective aldols. The dehalogenation of alkyl halides was achieved by a catalytic amount of InCl 3 in the presence of Bu 3 SnH. This procedure was applied to some representative cyclizations as radical proof. A simple and non‐toxic system, NaBH 4 /InCl 3 , also promoted dehalogenation, intramolecular cyclization, and intermolecular coupling reactions. In addition, the Et 3 SiH/InCl 3 system was found applicable to an effective intramolecular cyclization of enynes. © 2005 The Japan Chemical Journal Forum and Wiley Periodicals, Inc. Chem Rec 5: 323–335; 2005: Published online in Wiley InterScience ( www.interscience.wiley.com ) DOI 10.1002/tcr.20055