Stereoselective rhodium-catalyzed reaction of allenes with organoboronic reagents for diversified branched 1,3-alkadienes

• Published in: Nature communications 2024-09, Vol.15 (1), p.8344-11, Article 8344
• Main Authors: Wang, Weiyi, Hong, Shichao, He, Wenxiang, Zhang, Xue, Qian, Hui, Ma, Shengming
• Format: Article
• Language: English
• Subjects: 140/131; 140/58; 639/638/403/933; 639/638/77/888; Aromatic compounds; Biological activity; Catalysis; Chemical synthesis; Deuterium; Dienes; Efficiency; Humanities and Social Sciences; Isomerization; Isoprene; multidisciplinary; Natural products; Reagents; Rhodium; Science; Science (multidisciplinary); Stereoselectivity
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-024-52209-5

The terminal isoprene unit, as the simplest branched 1,3-diene unit, exists in a wide range of natural products and bioactive molecules. Herein, we report a stereoselective rhodium-catalyzed reaction of allenes with readily available methyl pinacol boronic ester, providing a straightforward approach to isoprene derivatives with a very high E -stereoselectivity. Its synthetic potential has been illustrated by a concise synthesis of natural product schinitrienin. Such a protocol can be easily extended to aryl and alkenyl boronic reagents affording 2-aryl or -alkenyl substituted 1,3-dienes, which are also of high importance in organic synthesis but remain challenging for their selective synthesis, with a remarkable stereoselectivity. A series of deuterium-labeling experiments indicate a unique mechanism, which involves reversible β -H elimination as well as hydrometalation and isomerization of the allylic rhodium species. The isoprene unit is widely found in bioactive molecules, but stereoselective synthetic methods for these 1,3-dienes remain limited. Here, the authors disclose an E-selective rhodium-catalyzed synthesis of terminal isoprene units from allenes.