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Please login or sign up for a free trial to access the full content. Variation 2: Alkylation of Alk-2-ynoic Acids or Their Salts

DOI: 10.1055/sos-SD-020-01178

Evano, G.Science of Synthesis, (2007201249.

Alk-2-ynoic acid esters can be obtained by alkylation of carboxylate salts, usually generated in situ with potassium carbonate or cesium carbonate, with suitable alkylating agents. A large number of simple alk-2-ynoic acid esters 16 have been prepared using this method (examples in Table 3). Good yields are usually obtained when the alkylating agent is a primary alkyl iodide, a benzylic or allylic bromide, or a sulfonate ester. The nucleophilic displacement requires the use of a polar aprotic solvent and dimethylformamide, dimethyl sulfoxide, or even hexamethylphosphoric triamide are used in most cases. With secondary and tertiary alkylating agents, elimination usually becomes a competitive reaction and the yields are considerably lower.

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Meeee M8 M8M Meee Meeeeeeeee Meeee (%) Mee
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8 8-MeM-8-MMM8M8 MeM MMM MMMM 88 [‌88‌]
8 (MM8)8Me MeM M8MM8 MMM, ee 88 [‌88‌]
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Meeeee 8 Meeeeeeee ee Mee-8-eeeee Meeeee Meeeee eeee Meeeeeeeeeee ee (Meeeeeeeeeeeee)eeeeeeeeeeee[‌88‌,‌88‌]

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Meeeee 8 Meeeeeeee ee Mee-8-eeeee Meee Meeeee Meeee Meeeeeeee Meeeeeeee[‌88‌,‌88‌‌88‌]

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Meeeee 8 Meeeeeeeeeeeeee Meeeeeeee ee Mee-8-eeeee Meee Meeeee Meeee Meeeeeeee ee Meeeeeee Meeeeeeeee[‌88‌]

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Meeeee 8-Meeeeeeeee-8-eeeeee (88, M8=Me; M8=Me); Meeeeee Meeeeeeee:[‌88‌]

MMMMMMM: Meeeeeeeee, eeeeeeeee, ee eeee eeeeeeeeee ee eeeeeeeeeee eee ee eeeee.

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(8M)-8-Meeeeeeeee-8-eeee 8-Meeeeeeeee-8-eeeeee [(M)-88]; Meeeeee Meeeeeeee:[‌88‌]

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