Reduction par les sels chromeux de bromures benzyliques ortho-o-acyles avec transposition du groupement acyle
作者:B. Ledoussal、A. Gorgues、A. Le Coq
DOI:10.1016/s0040-4020(01)87790-5
日期:——
σ-bonded organochromium (III) complexes resulting from the reduction of-O-acyl benzylicbromides with CrCl2., undergo an 1,5-transposition of the esteracyl functional group which allows, through selected experimental conditions either a selective access to the unmasked -hydroxybenl ketones or a new preparation of the 2-substituted benzo¦b¦furans . The scope and limitations of the method are presented
Catalytic Intramolecular Wittig Reaction Based on a Phosphine/Phosphine Oxide Catalytic Cycle for the Synthesis of Heterocycles
作者:Long Wang、Mei Sun、Ming-Wu Ding
DOI:10.1002/ejoc.201601628
日期:2017.5.10
The catalytic intramolecular Wittig reactions of carbonyl-containing bromides are reported. The R3PO byproducts participate in the catalytic cycle; therefore, the Wittig reaction can be accomplished with only a catalytic amount of organophosphorus reagent. The reaction has also been applied to the efficient and selective synthesis of isoquinolin-1(2H)-ones, indoles, 2,3-dihydro-1H-2-benzazepin-1-ones
The intramolecular condensation of o-acyloxybenzylidenetriphenylphosphoranes leads to acylated products in t-BuOH and to benzofurans in toluene. Mechanistic aspects are discussed. A general method is described for the synthesis of benzofurans from o-cresols, o-hydroxybenzylic alcohols, and deactivated phenols.
Chromium(II) salt mediated reductive transposition of an ester acyl group in ortho-O-acyl benzylic bromides: a ready access to unmasked ortho-hydroxybenzyl ketones and a new route to benzo[b]furans
作者:Beno�t Ledoussal、Alain Gorgues、Andr� Le Coq
DOI:10.1039/c39860000171
日期:——
The mono-σ-bonded organochromium(III) complexes (A) derived from (1) rearrange internally into (B) through an acylestergrouptransposition, selected experimental conditions allowing either a good access to the unmaskedortho-hydroxybenzylketones (2) or a newroute to the 2-substituted benzo[b]furans (3).
衍生自(1)的单σ键合有机铬(III)配合物通过酰基酯基转移在内部重新排列为(B),选择的实验条件使得可以很好地接触未掩盖的邻羟基苄基酮(2)或新的途径取代2-取代的苯并[ b ]呋喃(3)。
Unexpected migration of a benzoyl group in the intramolecular Wittig reaction of o-acyloxybenzylidenephosphoranes with benzoyl chlorides: One-pot synthesis of isomeric 3-benzoyl-2-phenylbenzofurans
The reaction of o-acyloxybenzylidenetriphenylphosphoranes with substituted benzoyl chlorides in an aprotic solvent led, together with the expected 2-phenylbenzofuran, to isomeric 3-benzoyl-2-phenylbenzofuran derivatives. This result formally corresponds to intramolecular migration of the benzoyl group from the ortho oxygen atom to the ylide carbanion via cyclization and ring opening of the starting