Enantioselective Synthesis of Acyclic Orthogonally Functionalized Compounds Bearing a Quaternary Stereocenter Using Chiral Ammonium Salt Catalysis

We herein report an asymmetric protocol to access a series of orthogonally functionalized acyclic chiral target molecules containing a quaternary stereogenic center by carrying out the enantioselective α-alkylation of novel orthogonally functionalized dioxolane-containing cyanoacetates under chiral ammonium salt catalysis. By using just 1 mol % of Maruoka's spirocyclic ammonium salt catalysts enantioselectivities up to e.r.=97.5 : 2.5 could be achieved and further functional group manipulations of the products were carried out as well.     

Synthesis of functionally substituted cyanoacetates

Some new cyanoacetates were synthesized and characterized. They are precursors for -cyanoacrylates used as rapidly polymerized, cold-hardening adhesives.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 3, pp. 523–525, March, 1993.     

Synthesis of functionally substituted 2-cyanoacrylates

The conditions for the Knoevenagel synthesis of 2-cyanoacrylates containing double and triple bonds in the alkoxycarbonyl group have been studied. It was found that the esters are formed in 10–70 % yields by the condensation of the respective cyanoacetates with formaldehyde in the 11 ratio in the presence of piperidine, followed by the pyrolysis of the oligomers formedin vacuo at 170–200 °C in the presence ofpara-toluenesulfonic acid. The compounds synthesized readily undergo polymerization at room temperature and can be used as the basis for thermostable rapidly polymerizing adhesives.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 4, pp. 646–649, April, 1994.     

Cross reactions of cyanoacetic acid derivatives with carbonyl compounds 3. One-step synthesis of substituted 2-amino-5-oxo-4,5-dihydropyrano[3,2-c]chromenes

Three-component reactions of 4-hydroxycoumarin, carbonyl compounds, and malono-nitrile or alkyl cyanoacetates in ethanol in the presence of Et₃N as a catalyst give substituted 2-amino-5-oxo-4,5-dihydropyrano[3,2-c]chromenes. Dedicated to Academician V. I. Minkin on the occasion of his 70th birthday. __________ Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 4, pp. 968–972, April, 2005.     

Electrochemically induced chain transformation of salicylaldehydes and alkyl cyanoacetates into substituted 4H-chromenes

Electrolysis of salicylaldehydes and alkyl cyanoacetates in ethanol in an undivided cell in the presence of sodium bromide results in the formation of substituted alkyl 2-amino-4-(1-cyano-2-alkoxy-2-oxoethyl)-4H-chromene-3-carboxylates in 85-95% yields.