132727-08-3Relevant academic research and scientific papers
α-Hydroxy-Tetrazoles as Latent Ethynyl Moieties: A Mechanistic Investigation
Quinodoz, Pierre,Wright, Karen,Drouillat, Bruno,Kletskii, Mikhail E.,Burov, Oleg N.,Lisovin, Anton. V.,Couty, Fran?ois
, (2018/05/03)
This article focuses on the dehydration of α-hydroxy-tetrazoles, leading to tetraazafulvenes and then to vinylic carbenes that rearrange into ethynyl moieties through the Fritsch-Buttenberg-Wiechell rearrangement. Each step of this sequence was scrutinized, either by examination of the substrate and/or dehydrating agent scope, or through AM1 calculations, in order to understand the limiting step of this process. This underrated transformation appears to be a viable alternative to existing methods used for transforming aldehydes into alkynes.
Influence of the acetylenic substituent on the intramolecular carbolithiation of alkynes
Girard, Anne-Lise,Lhermet, Rudy,Fressigne, Catherine,Durandetti, Muriel,Maddaluno, Jacques
scheme or table, p. 2895 - 2905 (2012/06/29)
The intramolecular carbolithiation of a series of propargylic ethers has been performed to evaluate the influence of the terminal substituent on the efficiency and the stereochemical outcome of the cyclization. Our results show that only 5-exo-dig cyclizations are observed, and dihydrobenzofurans are obtained exclusively. Depending on the nature of the terminal substituent, two cases can be considered. If the terminal substituent carried by the acetylenic carbon atom is itself a carbon atom, the cyclization can occur provided the terminal propargylic position bears a coordinating element and is at least disubstituted. When the cyclization occurs, it follows an anti-carbolithiation pathway and thus leads to the E isomer of the exocyclic double bond. Only in one case (Ph) was a mixture of the E and Z isomers of the resulting olefin recovered. The cyclization can also take place if the alkyne is directly substituted by S or Si, provided the cyclization conditions are tuned. In the case of the trimethylsilyl substituent, a syn-carbolithiation was observed. If the double bond is recovered, in most cases, in the exocyclic position, the products can aromatize directly for SPh-substituted substrate 24. Furthermore, in the two latter cases, when alkylation of the vinyllithium intermediate is performed, isomerization of the double bond seems instantaneous. Copyright
A two-step, formal [4 + 2] approach toward piperidin-4-ones via au catalysis
Cui, Li,Peng, Yu,Zhang, Liming
supporting information; experimental part, p. 8394 - 8395 (2009/10/23)
(Chemical Equation Presented) An efficient, formal [4 + 2] synthesis of synthetically valuable piperidin-4-ones from secondary amines in two steps has been achieved via a key gold catalysis without the purification of tertiary amine intermediates. This reaction is selective toward the less-substituted alkyl group and shows moderate to excellent diastereoselectivities. Its synthetic potential in alkaloid synthesis is demonstratedin a highly diastereoselective synthesis of (±)-cermizine C.
Preparation of the 4-hydroxytryptamine scaffold via palladium-catalyzed cyclization: A practical and versatile synthesis of psilocin
Gathergood, Nicholas,Scammells, Peter J.
, p. 921 - 923 (2007/10/03)
(Matrix presented) The 4-hydroxytryptamine scaffold of psilocin was successfully prepared via palladium-catalyzed cyclization of protected N-tert-butoxycarbonyl-2-iodo-3-methoxyaniline and an appropriately substituted silyl acetylene. Removal of the protecting groups afforded psilocin in good yield.
