Abstract
Investigation of titanium-centered metallacycle-mediated cross-coupling between unsymmetrical internal alkynes has led to the discovery that TMSCl significantly accelerates the [Formula presented] bond forming event. We report a collection of results that compare the efficiency of this reaction employing Ti(Oi-Pr)4/2n-BuLi in PhMe with and without TMSCl, demonstrating in every case that the presence of TMSCl has a profound impact on efficiency. While relevant in the context of developing this fundamental bond-forming process as an entry to more complex organometallic transformations, these modified reaction conditions allow coupling processes to be run at >10 times the concentrations previously possible [in 2.4 M n-BuLi (hexanes)], without the requirement of additional solvent. Finally, we demonstrate the effectiveness of these modified reaction conditions for the annulative cross-coupling between TMS-alkynes and 1,6-enynes leading to the formation of angularly substituted hydrindanes with, now well appreciated, high levels of regio- and stereoselection.
Original language | English |
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Pages (from-to) | 3848-3850 |
Number of pages | 3 |
Journal | Tetrahedron Letters |
Volume | 57 |
Issue number | 34 |
DOIs | |
Publication status | Published - 2016 |
Externally published | Yes |
Keywords
- 1,3-Dienes
- Directed reactions
- Metallacycle-mediated cross-coupling
- Titanium isopropoxide
ASJC Scopus subject areas
- Biochemistry
- Drug Discovery
- Organic Chemistry