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Syntheses of Cyclopropyl Silyl Ketones
Author(s) -
Scheller Markus E.,
Frei Bruno
Publication year - 1986
Publication title -
helvetica chimica acta
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.74
H-Index - 82
eISSN - 1522-2675
pISSN - 0018-019X
DOI - 10.1002/hlca.19860690107
Subject(s) - silylation , cyclopropanation , chemistry , trimethylsilyl , allylic rearrangement , aldehyde , ketone , medicinal chemistry , wittig reaction , organic chemistry , yield (engineering) , catalysis , materials science , metallurgy
The synthesis of the cyclopropyl silyl ketones 1 – 4 is described. The trimethylsilyl ketone 1 was prepared from geraniol (( E )‐ 5 ) in ca. 10% overall yield by cyclopropanation leading to 6 , CrO 3 oxidation to the aldehyde 8 , reaction of the latter with trimethylsilyl anion to 14A + B , and CrO 3 oxidation to 1 . Also for the ( t ‐butyl)dimethylsilyl ketones 2 – 4 , an efficient four‐step synthesis with overall yields of 48%, 85%, and 13%, respectively, was elaborated, starting from the allylic alcohols ( E )‐ 5 , and 23 . The method of preparation involves as the key step a Wittig rearrangement of the silylallyl ethers (( E / Z )‐ 20 , 24 ) to the silyl alcohols (( E / Z )‐ 21 , 25 ), subsequent cyclopropanation ( 19A + B , 22A + B , 26 ), and oxidation to the cyclopropyl silyl ketones 2 – 4 .