42017-15-2Relevant academic research and scientific papers
The chemistry of organoborates. 9. A regiospecific and highly stereoselective construction of trisubstituted αβ-unsaturated ketones, tetrasubstituted αβ-unsaturated ketones and specifically protected 1,3-diketones from alkynyltrialkylborates
Pelter,Colclough
, p. 811 - 828 (2007/10/02)
Lithium alkynyltrialkylborates react with dioxolanium fluorosulphonates in a highly stereoselective fashion such that the dioxolanium group and the migrating group and the migrating group are on the same side of the new alkene intermediate. Hydrolysis of the intermediate yields Z-trisubstituted αβ-unsaturated ketones in which all three substituents have different origins and can be independently varied. Oxidation of the intermediates gives β-ketoacetals, which are regiospecifically protected 1,3-diketones. If the initial intermediates are allowed to stand, then another migration occurs and tetra-substituted αβ-unsaturated ketones result.
REACTIONS OF TRIALKYLALKYNYLBORATES WITH 2-ALKYL-1,3-DIOXALAN-2-YLIUM FLUOROSULPHONATES. VERSATILE DIRECT ROUTES TO Z-αβ-UNSATURATED KETONES, SPECIFICALLY PROTECTED 1,3-DIKETONES AND OTHER KETONIC SPECIES.
Pelter, Andrew,Colclough, M. Eamon
, p. 1935 - 1938 (2007/10/02)
The reactions of 2-alkyl-1,3-dioxolan-2-ylium fluorosulphonates with trialkylalkynylborates proceed at the β-position of the alkynylborates and may be controlled to give either one or two migrations from boron to carbon.The one migration is stereospecific and the products on hydrolysis yield Z-αβ-unsaturated ketones, whilst oxidation gives specifically mono-protected 1,3-diketones.If the reactions are allowed to proceed for a longer time, then a second migration from boron to carbon occurs to yield intermediates that give other αβ-unsaturated ketones on oxidation.
THE REACTION OF LITHIUM TRIALKYL(1-ALKYNYL)BORATES WITH ORTHOESTERS IN THE PRESENCE OF TITANIUM TETRACHLORIDE. A NEW SYNTHESIS OF α,β-UNSATURATED CARBONYL COMPOUNDS
Hara, Shoji,Dojo, Hidetaka,Suzuki, Akira
, p. 285 - 286 (2007/10/02)
Trialkyl(1-alkynyl)borates readily available from trialkylboranes and lithium acetylides react with orthoesters in the presence of titanium tetrachloride, followed by the oxidation with hydrogen peroxide and sodium hydroxide to give the corresponding α,β-unsaturated carbonyl compounds.
