Thioamides, Quinolinium and Isoquinolinium Salts: Useful Synthons in the Synthesis of Heterocyclic Compounds and Asymmetric Synthesis of Sulfonic acid Derivatives

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Mirjafary, Zohreh | 2010

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Type of Document: Ph.D. Dissertation
Language: Farsi
Document No: 40655 (03)
University: Sharif University of Technology
Department: Chemistry
Advisor(s): Matloubi Moghaddam, Firouz
Abstract:
We have reported a new and efficient synthesis of a broad spectrum of heterotetracyclic benzoxazocines via unique tandem 1,3-dinucleophilic addition of different bifunctional nucleophiles to quinolinium and isoquinolinium salts. The reaction generally involves the initial addition of nucleophiles to quinolinium salts to form enamine intermediate which can be trapped by intramolecular O/S-alkylation of nucleophiles. This protocol is a very mild and simple method for construction of eight-membered ring in fused heterocycles in a one-step process. We have also developed an efficient asymmetric synthesis of α,β-disubstituted γ-bisalkoxycarbonyl and α, β- disubstituted γ- phosphono sulfonates via Michael addition of a lithiated sulfonate bearing 1,2:5,6-di-O-isopropylidene-α-D-allofuranose as a chiral auxiliary to Knoevenagel acceptors in good yields and excellent diastereoselectivities. The cleavage of the chiral sugar auxiliary demonstrated in typical case proceeded without any epimerization or racemization to form the corresponding isopropyl sulfonate in good overall yield and excellent diastereomeric and enantiomeric excess (de, ee ≥ 98%).
Keywords:
Thioamides ; Allofuranose ; Sulfonic Acid ; Tandem Reaction ; Dinucleophile ; Benzoxazocine ; Quinolinium Salt ; Asymmetric Synthesis

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