Synthesis of C5-Chain-Containing and Terminally Functionalized Propargyl Silanes and Their Cyclization Reactions with 1,2-Silyl Shift
RTU 63. studentu zinātniskās un tehniskās konferences tēzes 2022
Artjoms Ubaidullajevs, Māris Turks

In this work, a method for obtaining heterocyclic compounds from intramolecular nucleophiles was developed for propargylsilanes containing 1. In their reaction with electrophiles (Br+, I+, H+) vinyl cation 2 is formed, which further, as a result of migration of 1,2-silyl groups, they form a more stable allyl cation 3 [1], which, depending on the nucleophiles groups (G) and reaction conditions can cyclize to form one of compounds 6, 8 or 12 according to Scheme 1. The obtained products can serve as building blocks in the synthesis of biologically active compounds [2-3]. 6 functionalized propargylsilanes 1 were synthesized and their cyclization attempts were made. Cyclization reactions were performed at different temperatures (from ‒40 °C to 100 °C) in polar aprotic solvents (MeCN, DCM, THF), using halogen cation sources (NBS, NIS) or acid (HNTf2) as an electrophile in catalytic quantities. Depending on the synthesis route, the reaction takes from 5 minutes to 2 days. It was observed that the reactions that would lead to the formation of four-membered heterocycles failed to be realized, but two five-membered heterocycles - 4,5-dihydro-1,2-isoxazole derivatives were obtained. On the other hand, six-membered formation of heterocycles can be observed by both NMR and GC/MS results, but so far effective isolation and purification methods has not yet been found for the compounds.


Keywords
1,2-Silyl Shift, Cyclization, Heterocycles, Propargyl Silanes
Hyperlink
http://alephfiles.rtu.lv/TUA01/000083020_e.pdf#page=46

Ubaidullajevs, A., Turks, M. Synthesis of C5-Chain-Containing and Terminally Functionalized Propargyl Silanes and Their Cyclization Reactions with 1,2-Silyl Shift. In: RTU 63. studentu zinātniskās un tehniskās konferences tēzes, Latvia, Rīga, 22-22 April, 2022. Rīga: 2022, pp.46-46.

Publication language
Latvian (lv)
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