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Wu Y, Tian B, Witzel S, Jin H, Tian X, Rudolph M, Rominger F, Hashmi ASK. AuBr 3 -Catalyzed Chemoselective Annulation of Isocyanates with 2H-Azirine. Chemistry 2019; 25:4093-4099. [PMID: 30370953 DOI: 10.1002/chem.201804765] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2018] [Indexed: 01/19/2023]
Abstract
The chemoselective cyclization of isocyanates with 2H-azirine was achieved with AuBr3 as catalyst. This transfer sets the stage for the synthesis of aromatic oxazole-ureas in a tandem process. The addition of a catalytic amount of phosphite enhances the process enormously. The reaction can also be performed in a one-pot process using benzoyl azide instead of isocyanate under the same conditions. A detailed study on the role of the phosphite that was applied as an additive revealed that only non-coordinated phosphite can reduce gold(III) and that gold(I) coordinated phosphite is not oxidized. Accompanied by the reduction of gold, HBr is generated in situ, which turned out to be the actual promotor in combination with the remaining AuBr3 . The positive effect of acid can be explained by a strong N-Au coordination, which tends to break more easily in the presence of small amount of protic acid in the reaction solution.
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Affiliation(s)
- Yufeng Wu
- Organisch-Chemisches Institut, Universität Heidelberg, Im Neuenheimer Feld 270, 69120, Heidelberg, Germany
| | - Bing Tian
- Organisch-Chemisches Institut, Universität Heidelberg, Im Neuenheimer Feld 270, 69120, Heidelberg, Germany
| | - Sina Witzel
- Organisch-Chemisches Institut, Universität Heidelberg, Im Neuenheimer Feld 270, 69120, Heidelberg, Germany
| | - Hongming Jin
- Organisch-Chemisches Institut, Universität Heidelberg, Im Neuenheimer Feld 270, 69120, Heidelberg, Germany
| | - Xianhai Tian
- Organisch-Chemisches Institut, Universität Heidelberg, Im Neuenheimer Feld 270, 69120, Heidelberg, Germany
| | - Matthias Rudolph
- Organisch-Chemisches Institut, Universität Heidelberg, Im Neuenheimer Feld 270, 69120, Heidelberg, Germany
| | - Frank Rominger
- Organisch-Chemisches Institut, Universität Heidelberg, Im Neuenheimer Feld 270, 69120, Heidelberg, Germany
| | - A Stephen K Hashmi
- Organisch-Chemisches Institut, Universität Heidelberg, Im Neuenheimer Feld 270, 69120, Heidelberg, Germany.,Chemistry Department, Faculty of Science, King Abdulaziz University (KAU), 21589, Jeddah, Saudi Arabia
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Van Hecke K, Thi Ngan V, Nockemann P, Thijs B, Tho Nguyen M, Binnemans K, Van Meervelt L. Crystal structure and ab initio calculations of a cyano-carbamimidic acid ethyl ester. J Mol Struct 2008. [DOI: 10.1016/j.molstruc.2007.10.027] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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Peshakova LS, Kalcheva VB, Simov DA. 2-Aminooxazoles and their derivatives (review). Chem Heterocycl Compd (N Y) 1981. [DOI: 10.1007/bf00503649] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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