85895-55-2Relevant academic research and scientific papers
Preparation and Diels-Alder Reactivity of Several New Chalcogen-Halogen Substituted Butadienes
Bridges, Alexander J.,Fischer, John W.
, p. 2954 - 2961 (2007/10/02)
Addition of halogens and pseudohalogens across one ?-bond of 1,4-dichlorobut-2-yne, followed by a 1,4-elimination, is an efficient synthesis of several new polysubstituted butadienes.If the product dienes have a sulfur or selenium substituent they are quite reactive, undergoing cycloaddition with the moderately reactive dienophile methyl vinyl ketone at 20 deg C in the presence of boron trifluoride etherate.The regiochemistry of the cycloadditions was elucidated, and the limitations of the methodology are discussed.
THE DIELS-ALDER REACTIVITY OF SOME NEW SULFUR (SELENIUM) SUBSTITUTED HALOBUTADIENES
Bridges, Alexander J.,Fischer, John W.
, p. 447 - 450 (2007/10/02)
3-PhS(e)-(1),2-(di)halobutadienes undergo BF3 catalysed cycloadditions with methyl vinyl ketone at 25 deg C, to give good yields of adducts in which the regiochemistry of addition is mainly controlled by the sulfur (selenium) atom.
ENOL THIOETHERS AS ENOL SUBSTITUTES. AN ALKYLATION SEQUENCE.
Trost,Lavoie
, p. 5075 - 5090 (2007/10/02)
Ionic bromination of enol phenyl thiolethers forms predominantly to exclusively 2-(phenylthio)-3-bromo-1-alkenes, an enolonium equivalent. The allylic bromide participates in displacements with stabilized and nonstabilized nucleophiles. The ability to hydrolyze the enol thioethers to their corresponding ketones equates this sequence to an equivalence of an enolonium ion. The versatility of the sulfur in selective introduction of allylic hydroxyl and amino groups as well as the ability to directly replace the sulfur substituent by hydrogen or alkyl imparts special significance to this approach. The sequence is highly regio-and chemoselective. Applications include the synthesis of lanceol and bisabolene and the introduction of steroid side chains.
