- Rhodium(II)-catalyzed intramolecular annulation of 1-sulfonyl-1,2,3- triazoles with pyrrole and indole rings: Facile synthesis of N-bridgehead azepine skeletons
-
A convenient and efficient synthetic method has been developed to construct highly functionalized N-bridgehead azepine skeletons, which are of great importance in biological and pharmaceutical industry. The reaction proceeds through a rhodium(II) azavinyl carbene intermediate, which initiated the intramolecular C-H functionalization with pyrrolyl and indolyl rings. A variety of azepine derivatives were obtained in moderate to good yields under mild reaction conditions with high chemoselectivity. Several interesting derivatizations of the resulting products demonstrate that this method is synthetically valuable and useful. Heads up: A convenient and efficient synthetic method of highly functionalized N-bridgehead azepine skeletons was developed using a rhodium(II)-catalyzed intramolecular annulation of pyrrolyl and indolyl triazoles. Several interesting transformations of the products into poly-heterocyclic products and the reaction mechanism are disclosed. Ts=4-toluenesulfonyl.
- Yang, Jin-Ming,Zhu, Cheng-Zhi,Tang, Xiang-Ying,Shi, Min
-
supporting information
p. 5142 - 5146
(2014/05/20)
-
- Synthesis of pyrrole N-derivatives from oxazolidines
-
Transformations of oxazolidine derivatives synthesized from industrially produced amino alcohols, aldehydes, and ketones under basic or acidic catalysis lead to the formation of N-alkyl- and N-(hydroxyalkyl)-substituted pyrroles in 19-81% yields.
- Sadykov, E. Kh.,Stankevich,Lobanova,Klimenko
-
p. 219 - 224
(2014/04/17)
-
- Photosensitized oxidations of substituted pyrroles: Unanticipated radical-derived oxygenated products
-
(Chemical Equation Presented) Photooxidation of pyrrole adducts 7-10 has been investigated in order to establish a general reaction pattern andmechanism for the formation of the resulting oxygenated products. The reactions were performed in several solvents utilizing both type I and type II sensitizers. In most cases, photooxidations gave complex mixture of products. Among these products, 5,5- or 6,5-bicyclic lactams (11, 15, and 19), maleimide 12 unsaturated γ-lactams (16 and 20), 5-hydroxylactams (13, 17, and21), and 5-methoxylactams (14, 18, and22) wereisolated and characterized. Photooxidation of 2,5-dimethyl-substituted pyrrole 10 in aprotic solvents unexpectedly afforded aldehyde 23 as the major product. Moreover, photooxidation of pyrrole adduct 10 in protic solvents exclusively gave the unprecedented solvent-trapped products 24-27. The formation of products 11-22 was rationalized by the intermediacy of a commonendoperoxide intermediate, whichcould be formedby both type I and type II mechanisms. Compounds 23-27 were most probably formed via an electron-transfer mechanism. 2009 American Chemical Society.
- Alberti, Mariza N.,Vougioukalakis, Georgios C.,Orfanopoulos, Michael
-
supporting information; experimental part
p. 7274 - 7282
(2010/01/16)
-
- Inversion de polarite par les groupes phosphore: inversion de regioselectivite dans l'addition des nucleophiles sur les allenes actives par des groupes attracteurs
-
Change in the regioselectivity of the addition of nucleophilic compounds YH (ROH, RSH, RNH2) on α-allenic ketones and esters can be effected by using the triphenylphosphonio group as an umpolung agent.In this way α,β-unsaturated ketones and esters are obtained with heteroatomic substituents in the γ position.The umpolung scheme of the activated allene is characterized by a vinylphosphonium salt 7 or 10 as a synthetic equivalent of the a4 synthon .CH2-CH=CH-Z.The synthetic process requires three (Z = COCH3) or two (Z = CO2CH3) distinct manipulations and gives good overall yields (63 to 71percent).This umpolung method can also be applied to binucleophilic compounds as a new synthesis for functional heterocycles such as the substituted dioxan 15c or pyrrole 16d.Two separate side reactions of the intermediary phosphonium salts were found to occur: a) the isomerization of the vinylphosphonium salts with migration of the double bond, and, b) for β-substituted phosphonium salts, exchange of heteroatomic groups Y through elimination-addition.Both side reactions can however be completely controlled.
- Cristau, Henri-Jean,Viala, Jacques,Christol, Henri
-
p. 980 - 998
(2007/10/02)
-