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Synthesis of allenes by 1,6‐addition of organocuprates to polarized enynes
Author(s) -
Krause Norbert
Publication year - 1990
Publication title -
chemische berichte
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 0009-2940
DOI - 10.1002/cber.19901231114
Subject(s) - chemistry , pivalic acid , regioselectivity , allene , trimethylsilyl , alkyl , aryl , protonation , yield (engineering) , quenching (fluorescence) , medicinal chemistry , organic chemistry , catalysis , ion , materials science , physics , quantum mechanics , metallurgy , fluorescence
Ten β‐allenic esters, ketones, and thioesters 15 bearing alkyl, alkenyl, aryl, and trimethylsilyl groups are synthesized in 57‐ 85% yield by 1,6‐addition of organocuprates to polarized enynes 10. The dependence of the regioselectivity of the protonation of the allenyl enolate intermediate 7 on the protonating agent is studied: pure allenes are obtained by quenching the intermediate with pivalic acid at −80°C. The method is applied in a short synthesis of pseudoionone (18).