Aldehydes and ketones, on treatment with a low-valent cerium reagent, undergo reductive dimerization to produce the corresponding pinacols in high yield.
105 for the reduction to alcohol and pinacol formation, respectively, and are very stable so that they can be recycled for at least 10 times in the reactions without significant loss of catalytic activity. The additional advantages of this method include good functional group tolerance, mild reaction conditions, the allowance of selectively reducing aldehydes in the presence of ketones, and easiness
quantitative reduction of aromatic aldehydes, ketones, diketones and oxo aldehydes to alcohols by use of TiCl3/NH3 in aqueous methanol solution is reported. The reducing system distinguishes between different classes of aldehydes and/or ketones, and many functionalities that usually do not survive under reducing conditions are tolerated well. The concept of reversal of chemoselectivity has also been developed
Irradiation of aromatic carbonylcompounds and allyl-, 2-methyl-2-propenyl-, or 3-methyl-2-butenyltrimethylstannanes in acetonitrile afforded δ,γ-unsaturated alcohols as major product. A photoinduced electron transfer mechanism is proposed for the allylations.
Design of a Novel Cyclopropane Donor Bis(trimethylsilylmethyl)cyclopropane and Its Electron Transfer Reactions
作者:Akira Oku、Yoshihito Yamauchi、Marc Schroeder
DOI:10.1246/cl.2001.1194
日期:2001.11
A novel donor of SET reactions, 1,1-bis(trimethylsilylmethyl)-2-phenylcyclopropane (BTCP), was designed to function as a homoallylic 1-phenyl-3-(trimethylsilylmethyl)-3-butenyl radical (5). Thus, non-irradiated reaction of BTCP with DDQ or chloranil gave a six-membered cyclic compound, which corresponds to a Diels–Alder adduct of 3-trimethylsilylmethyl-1,3-butadiene derived from BTCP. The photoinduced