Cobalt-catalyzed deoxygenative triborylation of allylic ethers to access 1,1,3-triborylalkanes

• Published in: Nature communications Vol. 11; no. 1; pp. 5193 - 8
• Main Authors: Teo, Wei Jie, Yang, Xiaoxu, Poon, Yeng Yeng, Ge, Shaozhong
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 15.10.2020; Nature Portfolio
• Subjects: 140/131; 140/58; 639/638/403/934; 639/638/549/933; 639/638/77/888; Humanities and Social Sciences; multidisciplinary; Science; Science (multidisciplinary)
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-020-19039-7

Polyborylated organic compounds have been emerging as versatile building blocks in chemical synthesis. Here we report a selective cobalt-catalyzed deoxygenative 1,1,3-triborylation reaction of allylic ethers with pinacolborane to prepare 1,1,3-triborylalkane compounds. With naturally abundant and/or synthetic cinnamic methyl ethers as starting materials, we have achieved the synthesis of a variety of 1,1,3-triborylalkanes (25 examples). The synthetic utility of these 1,1,3-triborylalkanes is demonstrated through site-selective allylation, protodeborylation, and consecutive carbon-carbon bond-forming reactions. Mechanistic studies including deuterium-labeling and control experiments suggest that this 1,1,3-triborylation reaction proceeds through initial cobalt-catalyzed deoxygenative borylation of allylic ethers to form allylic boronates followed by cobalt-catalyzed 1,1-diborylation of the resulting allylic boronates. Organoboron compounds are versatile intermediates in chemical synthesis. Here, the authors report a selective cobalt-catalyzed deoxygenative triborylation of allylic ethers with pinacolborane to prepare 1,1,3-triborylalkane compounds.