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Conformationally Fixed Chiral Bisphosphine Ligands by Steric Modulators on the Ligand Backbone: Selective Synthesis of Strained 1,2-Disubstituted Chiral cis-Cyclopropanes
| Title: | Conformationally Fixed Chiral Bisphosphine Ligands by Steric Modulators on the Ligand Backbone: Selective Synthesis of Strained 1,2-Disubstituted Chiral cis-Cyclopropanes |
| Authors: | Iwamoto, Hiroaki Browse this author | | Ozawa, Yu Browse this author | | Hayashi, Yuta Browse this author | | Imamoto, Tsuneo Browse this author | | Ito, Hajime Browse this author →KAKEN DB |
| Keywords: | cis-Selective asymmetric cyclopropanation | | Asymmetric carboboration | | Chiral bisphosphine ligand, | | DFT calculation | | Copper(I)-catalysis |
| Issue Date: | 7-Jun-2022 |
| Publisher: | American Chemical Society |
| Journal Title: | Journal of the American Chemical Society |
| Volume: | 144 |
| Issue: | 23 |
| Start Page: | 10483 |
| End Page: | 10494 |
| Publisher DOI: | 10.1021/jacs.2c02745 |
| PMID: | 35702887 |
| Abstract: | A new series of C-1-symmetric P-chirogenic bisphosphine ligands of the type (R)-5,8-Si-Quinox-tBu(3)(Silyl = SiMe3, SiEt3, SiMe2Ph) have been developed. The bulky silyl modulators attached to the ligand backbone fix the phosphine substituents to form rigid chiral environments that can be used for substrate recognition. The ligand showed high performances for a copper(I)-catalyzed asymmetric borylative cyclopropanation of bulky silyl-substituted allylic electrophiles to afford higher disfavored 1,2-cis-silyl-boryl-cyclopropanes than the other possible isomers, trans-cyclopropane and allylboronate (up to 97% yield; 98% ee; cis/trans = >99:1; cyclopropane/allylboronate = >99:1 Detailed computational studies suggested that the highly rigid phosphine conformation, which is virtually undisturbed by the steric interactions with the bulky silyl-substituted allyl electrophiles, is key to the high stereo- and product-selectivities. Furthermore, the detailed computational analysis provided insight into the mechanism of the stereoretention or -inversion of the chiral alkylcopper(I) intermediate in the intramolecular cyclization. |
| Rights: | This document is the Accepted Manuscript version of a Published Work that appeared in final form in Journal of the American Chemical Society, copyright c American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work see https://pubs.acs.org/articlesonrequest/AOR-DGRBXANTVQWZGWJZ5UVX. |
| Type: | article (author version) |
| URI: | http://hdl.handle.net/2115/89563 |
| Appears in Collections: | 工学院・工学研究院 (Graduate School of Engineering / Faculty of Engineering) > 雑誌発表論文等 (Peer-reviewed Journal Articles, etc)
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Submitter: 伊藤 肇
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