Abstract
Alkenyl boronic esters are important reagents in organic synthesis. Herein, we report that these valuable products can be accessed by the homologation of boronic esters with lithiated epoxysilanes. Aliphatic and electron-rich aromatic boronic esters provided vinylidene boronic esters in moderate to high yields, while electron-deficient aromatic and vinyl boronic esters were found to give the corresponding vinyl silane products. Through DFT calculations, this divergence in mechanistic pathway has been rationalized by considering the stabilization of negative charge in the C-Si and C-B bond breaking transition states. This vinylidene homologation was used in a short six-step stereoselective synthesis of the proposed structure of machillene, however, synthetic and reported data were found to be inconsistent.
| Original language | English |
|---|---|
| Pages (from-to) | 15268-15272 |
| Number of pages | 5 |
| Journal | Angewandte Chemie-International Edition |
| Volume | 58 |
| Issue number | 43 |
| Early online date | 31 Jul 2019 |
| DOIs | |
| Publication status | Published - 21 Oct 2019 |
Keywords
- homologation
- natural product
- organoboron
- stereospecificity
- vinyl boronic ester
ASJC Scopus subject areas
- Catalysis
- Chemistry(all)
Cite this
Vinylidene Homologation of Boronic Esters and its Application to the Synthesis of the Proposed Structure of Machillene. / Fordham, James M; Grayson, Matthew N; Aggarwal, Varinder Kumar.
In: Angewandte Chemie-International Edition, Vol. 58, No. 43, 21.10.2019, p. 15268-15272.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Vinylidene Homologation of Boronic Esters and its Application to the Synthesis of the Proposed Structure of Machillene
AU - Fordham, James M
AU - Grayson, Matthew N
AU - Aggarwal, Varinder Kumar
N1 - © 2019 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
PY - 2019/10/21
Y1 - 2019/10/21
N2 - Alkenyl boronic esters are important reagents in organic synthesis. Herein, we report that these valuable products can be accessed by the homologation of boronic esters with lithiated epoxysilanes. Aliphatic and electron-rich aromatic boronic esters provided vinylidene boronic esters in moderate to high yields, while electron-deficient aromatic and vinyl boronic esters were found to give the corresponding vinyl silane products. Through DFT calculations, this divergence in mechanistic pathway has been rationalized by considering the stabilization of negative charge in the C-Si and C-B bond breaking transition states. This vinylidene homologation was used in a short six-step stereoselective synthesis of the proposed structure of machillene, however, synthetic and reported data were found to be inconsistent.
AB - Alkenyl boronic esters are important reagents in organic synthesis. Herein, we report that these valuable products can be accessed by the homologation of boronic esters with lithiated epoxysilanes. Aliphatic and electron-rich aromatic boronic esters provided vinylidene boronic esters in moderate to high yields, while electron-deficient aromatic and vinyl boronic esters were found to give the corresponding vinyl silane products. Through DFT calculations, this divergence in mechanistic pathway has been rationalized by considering the stabilization of negative charge in the C-Si and C-B bond breaking transition states. This vinylidene homologation was used in a short six-step stereoselective synthesis of the proposed structure of machillene, however, synthetic and reported data were found to be inconsistent.
KW - homologation
KW - natural product
KW - organoboron
KW - stereospecificity
KW - vinyl boronic ester
UR - http://www.scopus.com/inward/record.url?scp=85073183604&partnerID=8YFLogxK
U2 - 10.1002/anie.201907617
DO - 10.1002/anie.201907617
M3 - Article
VL - 58
SP - 15268
EP - 15272
JO - Angewandte Chemie-International Edition
JF - Angewandte Chemie-International Edition
SN - 1433-7851
IS - 43
ER -