190734-80-6Relevant academic research and scientific papers
α-(N-carbamoyl)alkylcuprate chemistry in the synthesis of nitrogen heterocycles
Dieter, R. Karl,Lu, Kai
, p. 847 - 855 (2007/10/03)
The conjugate adducts obtained via coupling of α-(N-carbamoyl)alkylcuprates with α,β-ynoates, α-allenyl esters, or α,β-enoates or enimides undergo N-Boc deprotection and cyclization onto the ester functionality upon treatment with PhOH/TMSCl, catecholboron bromide, or trimethylsilyl triflate. This two-pot sequence provides synthetic routes to 4-alkylidinepyrrolidine-2-ones, 4-alkylidinepyrrolizidin-2-ones, and 4-alkylidineindolizidin-2-ones via allenyl esters; pyrrolin-2-ones, tetrahydropyrrolizin-2-ones, and tetrahydroindolizin-2-ones via α,β-ynoates; pyrrolidin-2-ones, pyrrolizidin-2-ones, and indolizidin-2-ones via α,β-enoates or α,β-enimides. The reluctance of γ-carbamoyl-α,β-enoates to undergo E/Z isomerization requires the use of (Z)-β-iodo-α,β-enoates readily prepared by the addition of HI to the alkynyl esters for the efficient preparation of pyrrolinones, tetrahydropyrrolizinones, and tetrahydroindolizinones. Utilization of ω-functionalized α,β-ynoates or β-iodo-α,β-enoates allows for cyclization onto the ω-functionality providing for a synthetic route to quinolizidines.
Conjugate addition reactions of α-aminoalkylcuprates with α,β-alkenyl-, α,β-alkynyl-, α,β-allenyl-, and α,β-γ,δ-dienyl carboxylic acid derivatives, nitriles, and sulfoxides
Dieter,Lu,Velu
, p. 8715 - 8724 (2007/10/03)
α-Aminoalkylcuprates prepared from α-lithio carbamates and CuCN·2LiCl participate in 1,4-addition reactions with α,β-unsaturated esters, thiol esters, imides, and nitriles in poor to excellent yields depending upon the electron-withdrawing substituent and the substitution pattern of the unsaturated substrate. These reagents also undergo conjugate addition reactions with α,β-alkynyl esters, sulfoxides, and nitriles and with α,β-β,γ-unsaturated allenyl esters. Excellent stereocontrol is achieved in the conjugate additions of α-aminoalkylcuprates to the allenyl esters, while poor stereoselectivity results in the conjugate additions to the alkynyl derivatives. Deprotection and cyclization of the alkynyl adducts affords pyrrolin-2-ones, while similar treatment of the allenyl adducts affords 4-alkylidine- pyrrolidin-2-ones and pyrrolizidinones.
