A new synthesis of 2-sulfanyl allylic alcohols and α-sulfanyl ketones from carbonyl compounds and 1-chloroalkyl p-tolyl sulfoxides with carbon-carbon bond-formation
Reaction of lithium α-sulfinyl carbanions of 1-chloroalkyl p-tolyl sulfoxides with ketones or aldehydes at low temperature gave adducts in almost quantitative yields. Treatment of the adducts derived from ketones with trifluoroacetic anhydride (TFAA) in t
A new synthesis of α,α-disubstituted carbonyl compounds from carbonyl compounds with one-carbon homologation
Lithium α-sulfinyl carbanions of 1-chloroalkyl p-tolyl sulfoxides were reacted with carbonyl compounds to afford adducts in high to quantitative yields. The adducts were treated with t-BuMgCl or LDA to give magnesium or lithium alkoxides, which were treated with i-PrMgCl or t-BuLi to afford the enolate with one-carbon elongation through β-oxido carbenoids. The enolate intermediates were found to be able to be trapped with electrophiles to give α,α-disubstituted carbonyl compounds in moderate to good yields. As a whole, this procedure offers a new and good method for synthesis of α,α-disubstituted carbonyl compounds from carbonyl compounds with one-carbon homologation in only two synthetic steps.
Satoh, Tsuyoshi,Miyashita, Kohsuke
p. 4859 - 4864
(2007/10/03)
New Method for Generation of β-Oxido Carbenoid via Ligand Exchange Reaction of Sulfoxides: A Versatile Procedure for One-Carbon Homologation of Carbonyl Compounds
A new procedure for one-carbon homologation of carbonyl compounds is described.The method is based on the rearrangement of β-oxido carbenoid which is generated via the ligand exchange reaction of the sulfinyl group of α-chloro β-hydroxy sulfoxide with tert-butyllithium.Addition of the carbanion of aryl 1-chloroalkyl sulfoxides to carbonyl compounds gave the adducts in good yields.The β-oxido carbenoid rearrangement of the adducts gave one-carbon homologated carbonyl compounds having an α-alkyl substituent.A similar reaction of the adducts derived from carbonyl compounds with chloromethyl p-tolyl sulfoxide yielded a procedure for a methylene insertion.The stereochemistry of the β-oxido carbenoid rearrangenment is also discussed.
A novel method for generation of carbenoid from α-chloro sulfoxides: A new and versatile procedure for one-carbon homologation of carbonyl compounds to carbonyl compounds having an α-alkyl substituent
Addition of the carbanion of 1-chloroalkyl p-tolyl sulfoxides to carbonyl compound gave the adducts, which were treated with a base followed by t-butyllithium to afford one-carbon homologated carbonyl compounds having an alkyl group at the α-position, via the β-oxido carbenoids, in moderate to good yields.
Satoh, Tsuyoshi,Itoh, Norifumi,Gengyo, Kaoru,Yamakawa, Koji
p. 7543 - 7546
(2007/10/02)
1-Chloroalkyl p-Tolyl Sulfoxides as Acetylide Anion Equivalent: A Novel Synthesis Including Asymmetric Synthesis of Propargylic Alcohols from Carbonyl Compounds
Addition of the carbanion of 1-chloroalkyl p-tolyl sulfoxide to carbonyl compounds gave the adducts, which were heated in refluxing toluene or xylene to give vinyl chlorides in high overall yield.Dehydrochlorination of the vinyl chlorides with excess n-BuLi afforded propargylic alcohols in high yields.Asymmetric synthesis of both enantiomers of the propargylic alcohols was realized using optically active 1-chloroalkyl p-tolyl sulfoxide and aldehyde.
Satoh, Tsuyoshi,Hayashi, Yasumasa,Yamakawa, Koji
p. 2153 - 2158
(2007/10/02)
1-Chloroalkyl p-Tolyl Sulfoxides as Useful Agents for Homologation of Carbonyl Compounds: Conversion of Carbonyl Compounds to α-Hydroxy Acids, Esters, and Amides and α,α'-Dihydroxy Ketones
One-carbon homologation of carbonyl compounds to α-hydroxy acids, esters, and amides by the use of 1-chloroalkyl p-tolyl sulfoxide as a hydroxycarbonyl anion equivalent is reported.Oxidation of the vinyl chlorides, the intermediates of the above-mentioned
Satoh, Tsuyoshi,Onda, Ken-ichi,Yamakawa, Koji
p. 4129 - 4134
(2007/10/02)
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