75478-68-1Relevant articles and documents
Three-component coupling sequence for the regiospecific synthesis of substituted pyridines
Chen, Ming Z.,Micalizio, Glenn C.
supporting information; experimental part, p. 1352 - 1356 (2012/03/11)
A de novo synthesis of substituted pyridines is described that proceeds through nucleophilic addition of a dithiane anion to an α,β- unsaturated carbonyl followed by metallacycle-mediated union of the resulting allylic alcohol with preformed trimethylsilane-imines (generated in situ by the low-temperature reaction of lithium hexamethyldisilazide with an aldehyde) and Ag(I)- or Hg(II)-mediated ring closure. The process is useful for the convergent assembly of di- through penta-substituted pyridines with complete regiochemical control.
ADDITION CONJUGUEE DE DERIVES LITHIES DE DITHIANE-1,3 AUX ALDEHYDES αβ ETHYLENIQUES
Wartski, L.,Bouz, M. El
, p. 3285 - 3289 (2007/10/02)
In order to synthesize γ carbonyl aldehydes which are interesting precursors in organic synthesis, we examine the action of masked acylanions, the lithiated derivatives from 1,3-dithiane 1a and 2-phenyl-1,3-dithiane on selected unsaturated aldehydes: crotonaldehyde 2, cinnamaldehyde 3, 3-methyl butenal 4 and methacrolein 5.In THF 1a leads with the four aldehydes to allylic alcohols.However 1b gives products resulting from C=C and C=O additions.Using THF-HMPA, we show that C=C addition is generally enhanced.Furthermore, in all cases examined C=C and C=O addition take place under kinetic controll: the regioselectivity observed can be interpreted by repulsive interactions due to the substrate and the reagent structure as well as lithium-carbonyl compound interactions.