72653-48-6Relevant academic research and scientific papers
Thioalkylation of Enolates, II. α-Thioalkylation of Zinc Enolates to α,α-Disubstituted Ketones
Groth, Ulrich,Huhn, Thomas,Richter, Norbert
, p. 49 - 54 (2007/10/02)
An α-alkylation of the 2-methylcycloalkanones 1 and 4 at the higher substituted carbon can be achieved by thioalkylation of the corresponding zinc enolates with the α-chlorosulfides 3.The desulfurization can be carried out with either Raney nickel or lithium in diethylamine for compounds which contain double or triple bonds. Key Words: Zinc enolates, thioalkylation of / Ketones, α,α-disubstituted / Desulfurization
α-ALKYLATION AND α-ALKYLIDENATION OF CARBONYL COMPOUNDS BY O-SILYLATED ENOLATE PHENYLTHIOALKYLATION
Paterson, Ian
, p. 4207 - 4220 (2007/10/02)
For many reactions next to a carbonyl group, the use of O-silylated enolate chemistry offers improvements in yield and selectivity over the corresponding reactions of Group I metal enolates.In the case of α-alkylation of carbonyl compounds, Lewis acid (TiCl4 or ZnBr2) promoted phenylthioalkylation of O-silylated enolates 3 by α-chlorosulphides 4 (R3=H, Me, Prn, Pri, Bui, and Me3Si), followed by reductive sulphur removal by Raney nickel, 5->6, is found to be a reliable method for this synthetically important C-C bond forming step.An alternative sulphur elimination pathway via the sulphoxide, 5->7, allows the regio- and stereocontrolled α-alkylidenation of carbonyl compounds.The phenylthioalkylation reaction is applicable to ketones, aldehydes, esters, and lactones.
Diastereoselectivity in the Diels-Alder Reactions of Thioaldehydes
Vedejs, E.,Stults, J. S.,Wilde, R. G.
, p. 5452 - 5460 (2007/10/02)
The Diels-Alder reaction of thioaldehydes with cyclopentadiene occurs with a preference for the endo isomer.The highest selectivity is observed for thioaldehydes RCHS where R is a bulky group such as tert-butyl or isopropyl.Thioaldehydes having α-alkoxy, acetoxy, or siloxy substituents also react with useful endo selectivity.Secondary orbital overlap is a small factor in these reactions since α-oxo thioaldehydes react with relatively low endo selectivity.Steric effects are primarily responsible for the endo preferences observed.The Diels-Alder reactions of chiral α-oxygen substituted thioaldehydes also occur with useful thioformyl face selectivity.A Cornforth transition state 5 is most likely for the selectivity observed for α-alkoxy or acetoxy thioaldehydes, but the α-hydroxy analogue 23 reacts with the opposite facial preference.The highest face selectivity is obtained with the acetonide of thioglyceraldehyde, generated by photolysis of the phenacyl sulfide 15b.
α,β-Epoxy Sulfoxides as Useful Intermediates in Organic Synthesis. I. A Novel Synthesis of Dialkyl Ketones and a Synthesis of Aldehydes from Ketones by One Carbon Elongation
Satoh, Tsuyoshi,Kaneko, Youhei,Izawa, Takao,Sakata, Kiichi,Yamakawa, Koji
, p. 1983 - 1990 (2007/10/02)
Treatment of α,β-epoxy sulfoxides, prepared from 1-chloroalkyl phenyl sulfoxides with ketones or aldehydes, with sodium benzeneselenolate gives dialkyl ketones or aldehydes in good yields under mild conditions.The mechanism of this reaction and an application of this process to a formal total synthesis of dihydrojasmone are described.
α-Alkylation and α-alkylidenation of carbonyl compounds: Lewis acid-promoted phenylthioalkylation of o-silylated enolates
Paterson, Ian,Fleming, Ian
, p. 2179 - 2182 (2007/10/11)
The O-silylated enolates of ketones, aldehydes, esters, and lactones can be phenylthioalkylated in the presence of Lewis acids; reductive or oxidative sulphur-removal gives the regiospecifically α-alkylated or alkylidenated carbonyl compounds.
