- Chemoselective intramolecular alkylation of the Blaise reaction intermediates: Tandem one-pot synthesis of exo -cyclic enaminoesters and their applications toward the synthesis of N -heterocyclic compounds
-
The intramolecular alkylative reactivity and N/C selectivity of the various Blaise reaction intermediates, which are formed from the reaction of the Reformatsky reagents with ω-chloroalkyl nitriles, did not reach the synthetic potential as an entry to exo-cyclic enaminoesters. To circumvent this issue, various additives were investigated, among which the addition of NaHMDS dramatically enhanced the reactivity and N/C selectivity. This modification provided a highly efficient route for the synthesis of various N-fused heterocyclic compounds, as it requires only two steps from nitriles.
- Kim, Ju Hyun,Shin, Hyunik,Lee, Sang-Gi
-
experimental part
p. 1560 - 1565
(2012/04/04)
-
- Tandem transformations of nitriles into N-heterocyclic compounds by electrophilic trapping of Blaise reaction intermediates
-
Tandem transformations of nitriles into various N-heterocycles have been accomplished through the reaction of electrophiles with Blaise reaction intermediates formed in situ. The reaction of the Blaise reaction intermediates with propiolates gives 2-pyridones through consecutive C- and N-nucleophilic reactions. The tandem reactions of the Blaise reaction intermediate with 1,3-enynes proceed through C-nucleophilic addition followed by an electrocyclization-aromatization cascade to give pyridines. Exocyclic enamino esters can be prepared by transformations of ω-chloroalkyl nitriles through chemoselective intramolecular alkylation of the Blaise reaction intermediate. Palladium-catalyzed intramolecular arylations or copper-catalyzed intermolecular cross-coupling reactions of the Blaise reaction intermediate give a range of indole derivatives. Combinations of tandem alkylations and palladium-catalyzed couplings of the Blaise reaction intermediates of ω-chloroalkyl nitriles give N-fused indoles. Georg Thieme Verlag Stuttgart · New York.
- Kim, Juhyun,Chun, Yusung,Shin, Hyunik,Lee, Sang-Gi
-
experimental part
p. 1809 - 1817
(2012/08/08)
-
- A convenient protocol for the alkylidenation of lactams
-
A convenient two-step preparation of alkylidenepyrrolidines is reported. Georg Thieme Verlag Stuttgart.
- Elliott, Mark C.,Wordingham, Stuart V.
-
p. 1162 - 1170
(2007/10/03)
-
- Silver-catalyzed hydroamination: Synthesis of N-bridgehead pyrroles, incorporating a protection-deprotection strategy for preparation of cyclic secondary vinylogous carbamates
-
N-Bridgehead pyrroles are efficiently prepared from cyclic secondary vinylogous carbamates using a two-step sequence. This sequence involves C-propargylation followed by a silver-catalyzed intramolecular hydroamination. Hydroamination is brought about using microwave irradiation and affords the desired N-bridgehead pyrroles rapidly and in good yield. Cyclic secondary vinylogous carbamates are prepared using a mild, economical procedure. Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005.
- Robinson, Ross S.,Dovey, Martin C.,Gravestock, David
-
p. 505 - 511
(2007/10/03)
-
- A versatile route to β-enamino esters by acylation of lithium enamines with diethyl carbonate or benzyl chloroformate
-
A versatile route to β-enamino esters 1, using accessible starting materials, was developed. Lithiated enamines are allowed to react with diethyl carbonate or benzyl chloroformate with the formation of the β-enamino esters 1a or 1b. The reaction is rather general from a wide array of ketimines and aldimines. Products included cyclic β-enamino esters 1aa-ac, very useful for the synthesis of natural products.
- Bartoli, Giuseppe,Cimarelli, Cristina,Dalpozzo, Renato,Palmieri, Gianni
-
p. 8613 - 8622
(2007/10/02)
-
- Application of the Intramolecular Aza-Wittig Reaction to the Synthesis of Vinylogous Urethanes and Amides
-
The treatment of ω-azido β-dicarbonyl derivatives with 1 equiv of triphenylphosphine leads to a transient phosphinimine (Staudinger reaction), which cyclizes into vinylogous urethanes and amides via an intramolecular aza-Wittig reaction in excellent yields.The starting azides were obtained by a nucleophilic substitution by NaN3 in Me2SO on the corresponding ω-halo β-dicarbonyl derivatives that were accessible by the γ-alkylation of β-dicarbonyl compounds with α,ω-dihaloalkanes.
- Lambert, P. H.,Vaultier, M.,Carrie, R.
-
p. 5352 - 5356
(2007/10/02)
-
- Thermolyse des β-enaminodiesters cycliques : acces a divers β-enaminoesters, β-enamino-thioesters et β-enaminoamides
-
A new synthesis of β-enaminoesters, β-enaminothioesters et β-enaminoamides by thermic decomposition of β-enaminodiesters is described.
- Celerier, J. P.,Maitte, P.
-
p. 963 - 964
(2007/10/02)
-