167902-86-5Relevant academic research and scientific papers
Lithiated 3-Tosylpropanal and 4-Tosyl-2-butanone Dimethyl Acetals as β-Acylvinyl Anion Equivalents for the Synthesis of Unsaturated 1,4-Dicarbonyl Compound and α,β-Butenolides
Bonete, Pedro,Najera, Carmen
, p. 2763 - 2776 (2007/10/02)
The lithiation of 1,1-dimethoxy-3-tosyllpropane (7a) and 2,2-dimethoxy-4-tosylbutane (7b) followed by reaction with acyl chlorides affords, after p-toluenesulfinic acid elimination, ene-1,4-dicarbonyl compounds in a stereoselective manner.In the case of compound 7a, derived from acrolein, sequential monolithiation and reaction with carbonyl compounds give cyclic acetals, which after oxidation and elimination of p-toluenesulfinic acid are transformed into α,β-butenolides.
Lithium 3-Lithio-3-tosylalkanoates: β-Acylvinyl Anion Equivalents of β-Lithiated α,β-Unsaturated Carboxylic Acids
Bonete, Pedro,Najera, Carmen
, p. 3202 - 3209 (2007/10/02)
The dilithiation of β-tosylated propanoic, 2-methylpropanoic, and butanoic acid 10 with n-butyllithium at -78 deg C leads to the corresponding lithium 3-lithio-3-tosylalkanoates 11.They react with different electrophilic reagents (deuterium oxide, iodine, trimethylchlorosilane, alkyl halides, and acyl chlorides) to give the corresponding 3-substituted tosylated alkanoic acids 12.When carbonyl compounds are allowed to react with intermediates 11 followed by in situ lactonization with trifluoroacetic anhydride and base-promoted elimination α,β-butenolides are obtained.This methodology is applied to the direct synthesis of the rosefuran lactone precursor 14cg, the O-benzyl derivative of (+/-)-umbelactone (14ch), and (+/-)-andirolactone (14ci).The alkylation and acylation reactions of organolithium compounds 11 followed by esterification with hydrogen chloride in methanol and treatment with 1,8-diazabicycloundec-7-ene (DBU) afford α,β- and/or β,γ-unsaturated esters 17 and/or 18 and unsaturated 4-keto esters 19, respectively.The last methodology has been applied to the synthesis of the unsaturated 4-keto ester 19ae precursor of the seco acid of (+/-)-pyrenophorin (22).
Lithium 3-lithio-3-tosylpropanoate: A useful α-tosylated homoenolate anion
Bonete,Najera
, p. 4065 - 4068 (2007/10/02)
Lithium 3-lithio-3-tosylpropanoate prepared by dilithiation of 3-tosylpropanoic acid with n-butyllithium at -78°C, reacts with different electrophiles yielding the expected 3-functionalized tosylated propanoic acids. When carbonyl compounds are used as electrophiles the corresponding α,β-butenolides are prepared directly.
