Synthesis of Vinyl Chromanes from Propargyl Silanes via Tandem Electrophilic Activation – 1,2-Silyl Shift – Friedel–Crafts Cyclization
24th Tetrahedron Symposium 2024
Artjoms Ubaidullajevs, Rasma Kroņkalne, Māris Turks

Here we report a new synthetic route to substituted 4-vinyl chromanes. The key synthetic step involves electrophilic activation of propargyl silanes 2 followed by tandem 1,2-silyl shift – Friedel–Crafts cyclization. Propargyl silanes 2 can be obtained from commercially available pent-4-yn-1-ol (1) in 3 steps: O-silylation, retro-Brook rearrangement under Schlosser conditions and modified Mitsunobu reaction with corresponding phenols. Additionally, halogen atom moiety can be introduced in the terminal alkyne position via silver(I) catalysis. Resulting propargyl silanes 2 in the presence of strong Brønsted acids undergo cyclization to yield vinyl chrormanes 3, whereas E-selective haloalkyne cyclization leads to stereodefined olefin side chain.


Keywords
1,2-Silyl Shift, Friedel–Crafts Cyclization, Chromanes, Propargyl Silanes

Ubaidullajevs, A., Kroņkalne, R., Turks, M. Synthesis of Vinyl Chromanes from Propargyl Silanes via Tandem Electrophilic Activation – 1,2-Silyl Shift – Friedel–Crafts Cyclization. In: 24th Tetrahedron Symposium, France, Montpellier, 18-21 June, 2024. Montpellier: 2024, pp.1-1.

Publication language
English (en)
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