83655-42-9Relevant articles and documents
Direct Enantioselective and Regioselective Alkylation of β,γ-Unsaturated Carboxylic Acids with Chiral Lithium Amides as Traceless Auxiliaries
Yu, Kai,Miao, Bukeyan,Wang, Wenqi,Zakarian, Armen
supporting information, (2019/03/19)
Efficient asymmetric alkylation of β,γ-unsaturated carboxylic acids without prior functionalization is enabled by chiral lithium amides. Enantioselectivity is imparted by a putative mixed lithium amide-enediolate aggregate that acts a traceless auxiliary formed in situ, allowing for a direct asymmetric alkylation and a simple recovery of the chiral reagent.
Synthesis of isochroman-3-ylacetates and isochromane-γ-lactones through rearrangement of aryldioxolanylacetates
Giles, Robin G. F.,Rickards, Rodney W.,Senanayake, Badra S.
, p. 3949 - 3956 (2007/10/03)
Lewis acid catalysed rearrangement of methyl 4,5-trans-4-aryldioxolan-5-ylacetates 1 provides a convenient route to substituted methyl isochroman-3-ylacetates 2 and isochromane-γ-lactones 3. The choice of Lewis acid is determined by the substitution pattern of the aromatic ring. The two contiguous isochromane stereocentres are transferred unchanged from the parent dioxolanes, while the configuration of the isochromane methyl group is dependent upon the aryl substitution, the reagent and the reaction conditions. Thus treatment of the C-2 epimeric 3′,5′-dimethoxyphenyldioxolanes 4 and 5 with camphorsulfonic acid afforded a mixture of the C-5 epimeric isochromane lactones 26 and 29, the former being favoured at lower acid concentrations, the latter at higher concentrations. Titanium tetrachloride isomerised the analogous 2′-chloro-5′-methoxyphenyldioxolanes 6 and 7 into the methyl isochroman-3-ylacetate 38, which could be lactonised to the isochromane lactone 27. Phosphoric acid converted the 2′,5′-dimethoxyphenyldioxolanes 8 and 9 into a mixture of the isochromane lactones 28 and 31, while similar treatment of the hydroxylactone 22 in the presence of acetaldehyde afforded the isochromane lactone 28 directly and with complete diastereoselectivity. Oxidative demethylation and annulation of this isochromahe lactone 28 afforded 5-epi-7-deoxykalafungin 41.
Studies on Simplified Ergoline Derivatives. A General Six-Step Synthesis of Phenyl-Substituted 4-Methyl-3,4,4a,5,6,10b-hexahydrobenzoquinolin-1-(2H)-one Analogs (1)
Salley, John J.,Glennon, Richard A.
, p. 545 - 550 (2007/10/02)
This communication outlines the development of a novel, general synthetic route to substituted α-tetralones 5, their subsequent conversion to the α,β-unsaturated ketones 11, and an improved, one-step transformation of 11 to the tricyclic title compounds 1.Thus, substituted derivatives of 1 can be prepared in six steps from simple benzaldehydes, or, in three steps from more readily available α-tetralones.
