16061-69-1Relevant academic research and scientific papers
A Comparison of the Reactions of lithium with α,β-Unsaturated Ketones and Those of Other Acyl Anion Equivalents Containing Sulfur
Ager, David J.,East, Michael B.
, p. 3983 - 3992 (2007/10/02)
The factors influencing the site of attack of lithium (1) with enones were investigated.Cyclohexenone (2) was chosen as a model compound, and conjugate addition occurred in THF-HMPA or DME; this mode of addition was also promoted by a potassium counterion.When the reaction was carried out with other enones, conjugate addition in THF-HMPA or DME was only observed if the β-position or the α,β-unsaturated ketone was not disubstituted. 1,4-Addition of 1 could be accomplished by preparation of the cuprate.The use of this approach was illustrated by a preparation of 4,4-dimethylcyclopent-2-en-1-one (28).For determination of the influence of DME on the regiochemical control of the addition of other sulfur-containing anions to enones, the study was extended to the anions derived from 1,3-dithian (29), bis(phenylthio)methane (30), bis(phenylthio)(trimethylsilyl)methane (35), and bis(trimethylsilyl)(phenylthio)methane (36).With these anions, DME did not promote conjugate addition to any significant extent.
SYNTHESIS OF SINGLE ISOMERS (E OR Z) OF PROTECTED γ,δ-UNSATURATED KETONES BY THE HORNER-WITTIG REACTION
Cornish Christopher A.,Warren, Stuart
, p. 2585 - 2598 (2007/10/02)
The lithium derivative of the γ-diphenylphosphinoyl ketal (10a) added to aldehydes and ketones to give stable Horner-Wittig intermediates (11) which were separated and converted into single isomers (E or Z) or γ,δ-unsaturated ketals (12). erythro-Adducts (11) and hence Z-(12), were selectively formed by addition of aldehydes and threo adducts (11), and hence E-(12), by reduction of the corresponding α-diphenylphosphinoyl ketones (13), prepared by acylation of the same γ-diphenylphosphinoyl ketal (10a).
