New selective cyclizations of alk-4-ynals with primary amines and azoles:one-pot synthesis of 2-azolylpyrrolidines and 3-iminocyclopentenes
摘要:
One-pot cyclization of alk-4-ynals with primary aliphatic amines and azoles in DMSO under the action of KOH affords 1-alkyl-2-azolyl-5-arylmethylidenepyrrolidines. Similar pro-cesses with lithium monoalkylamides in THE give rise to 3-iminocyclopentenes.
Divergent synthesis is a powerful strategy for the fast assembly of different molecular scaffoldsfrom identical starting materials. We describe here a solvent-controlled photocatalytic divergent cyclization of alkynyl aldehydes with sulfonyl chlorides for the direct construction of highly functionalized cyclopentenones and dihydropyranols that widely exist in bioactive molecules and natural products
Cyclization of alk-4-ynals with o-diaminoarenes as a selective one-pot synthesis of arylmethylidene-substituted 2,3-dihydro-1H-pyrrolo[1,2-a]benzimidazoles and 7,8-dihydro-6H-pyrrolo[1’,2’:1,2]imidazo[4,5-b]pyridines
作者:V. D. Gvozdev、K. N. Shavrin、E. G. Baskir、M. P. Egorov、O. M. Nefedov
DOI:10.1007/s11172-016-1517-6
日期:2016.7
3-diaminopyridine gave 7,8-dihydro-6H-pyrrolo[1’,2’:1,2]imidazo[4,5-b]pyridines in up to 56% yields. The distinguishing feature of the processes under study is proceeding of their key step that is intramolecular hydroamination of the triple bond, as a 5-exo-dig-cyclization. The necessity for the application of drastic conditions required for these processes is in agreement with the results of quantum chemical
A new synthesis of bicyclic N,O- and N,S-enaminals by the anionic cyclization of alk-4-ynals with amino alcohols and amino thiols
作者:V. D. Gvozdev、K. N. Shavrin、O. M. Nefedov
DOI:10.1007/s11172-014-0445-6
日期:2014.2
A reaction of alk-4-ynals with aliphatic amino alcohols or 2-aminoethanethiol in the system DMSO—KOH gives bicyclic N,O- and N,S-enaminals: 6-methylidenehexahydro-2H-pyrrolo[2,1-b][1,3]oxazines, 5-methylidenehexahydropyrrolo[2,1-b]oxazoles, or 5-methyl-idenehexahydropyrrolo[2,1-b]thiazoles. The reaction proceeds through the formation of equilibrium mixtures of the corresponding imines and monocyclic aminals with subsequent 5-exodig-cyclization catalyzed by the superbasic system DMSO-KOH.
One-pot synthesis of 1-arylmethylidene-1,2,3,3a-tetrahydro-5H-pyrrolo[1,2-a]-[3,1]benzoxazines and 1-arylmethylidene-1,2,3,3a,4,5-hexahydropyrrolo[1,2-a]-quinazolines from 5-arylalk-4-ynals and o-aminobenzylic alcohol/amine
作者:Valentin D. Gvozdev、Konstantin N. Shavrin、Mikhail P. Egorov、Oleg M. Nefedov
DOI:10.1016/j.mencom.2015.09.002
日期:2015.9
Cyclization of 5-arylalk-4-ynals with o-aminobenzylamine or o-aminobenzyl alcohol in DMSO under the sequential action of NH4Br and KOH affords (E)-1-arylmethylidene-1,2,3,3 a,4,5-hexahydropyrrolo[1,2-a]quinazolines or (E)-1-arylmethylidene-1,2,3,3a-tetrahydro-5H-pyrrolo-[1,2-a][3,1]benzoxazines;the latter without substituents in the 3-position easily isomerize into the corresponding 2-arylmethyl-1-(2-hydroxymethylphenyl)pyrroles.
Synthesis of 6-(arylmethylidene)octahydropyrrolo[1,2-a]pyrimidines and 5-(arylmethylidene)hexahydropyrrolo[1,2-a]imidazoles by the interaction of alk-4-ynals with a,?-diaminoalkanes in DMSO in the presence of KOH
作者:Konstantin N. Shavrin、Valentin D. Gvozdev、Oleg M. Nefedov
DOI:10.1016/j.mencom.2013.05.006
日期:2013.5
Cyclization of alk-4-ynals with alpha,omega-diaminoalkanes in DMSO under the action of KOH affords bicyclic N,N-enaminals - 6-(arylmethylidene)octahydro[1,2-a]pyrimidines and 5-(arylmethylidene)hexahydro[1,2-a]imidazoles.