Organic Superbases in Annulation with Propargylic Alcohols: Straightforward Synthesis of the Functionalized Oxazolopyrrolohexahydropyrimidine and Oxazolohexahydropyrimidoazepine Scaffolds. Issue 33 (4th November 2016)

• Record Type: Journal Article
• Authors: Trofimov, Boris A.; Shemyakina, Olesya A.; Mal'kina, Anastasiya G.; Stepanov, Anton V.; Volostnykh, Ol'ga G.; Ushakov, Igor' A.; Vashchenko, Alexander V.
• Is Part Of: European journal of organic chemistry. Issue 33(2016)
• Page Start: 5465
• Page End: 5469
• Publication Date: 2016-11-04
• Subjects: Alcohols -- Alkynes -- Annulation -- Nucleophilic addition -- Superbases; Chemistry, Organic -- Periodicals; Organic compounds -- Synthesis -- Periodicals; Bioorganic chemistry -- Periodicals; Chemistry, Physical organic -- Periodicals; 547
• DOI: 10.1002/ejoc.201600977
• Languages: English
• ISSNs: 1434-193X

Abstract

Abstract : The popular organic superbases 1, 5‐diazabicyclo[4.3.0]non‐5‐ene (DBN) and 1, 8‐diazabicyclo[5.4.0]undec‐7‐ene (DBU) underwent annulation with electron‐deficient propargylic alcohols [EWG = CN, C(O)Ph, CO2 Me] to afford functionalized condensed hexahydropyrimidine systems, [1, 3]oxazolo[3, 2‐ a ]pyrrolo[2, 1‐ b ]hexahydropyrimidines and [1, 3]oxazolo[3′, 2′:3, 4] hexahydropyrimido[1, 2‐ a ]azepines, in good to high yields. The reactions proceeded regioselectively and, in most cases, stereoselectively under mild conditions (without catalyst, 20–25 °C). The synthesized compounds, owing to their potential rich chemistry, are novel promising precursors for pyrimidine‐based pharmaceuticals. Abstract : The popular organic superbases 1, 5‐diazabicyclo[4.3.0]non‐5‐ene (DBN) and 1, 8‐diazabicyclo[5.4.0]undec‐7‐ene (DBU) undergo annulation with electron‐deficient propargylic alcohols [EWG = CN, C(O)Ph, CO2 Me] to afford functionalized condensed hexahydropyrimidines, [1, 3]oxazolo[3, 2‐ a ]pyrrolo[2, 1‐ b ]hexahydropyrimidines and [1, 3]oxazolo[3′, 2′:3, 4] hexahydropyrimido[1, 2‐ a ]azepines, in good to high yields.