68703-09-3Relevant articles and documents
Dichotomous stereocontrol in Claisen-Schmidt condensations: Synthesis of a propeller shaped rigid system
Aswathi, C. S.,Nithya, C.,Saumya, T. S.
supporting information, (2021/09/06)
Generally, Claisen-Schimdt condensation produces E-isomers of enones. However, in the Claisen Schimdt condensation between tetrahydropentalene-2,5(1H,3H)-dione and aromatic aldehydes, though initial condensations proceeded with the expected stereochemistry, subsequent condensations, where possible, produced the unexpected Z-isomers.
General Approach to the Synthesis of Poliquinenes. 8. Synthesis of Triquinacene, 1,10-Dimethyltriquinacene, and 1,10-Cyclohexanotriquinacene
Gupta, Ashok K.,Lannoye, Greg S.,Kubiak, Greg,Schkeryantz, Jeff,Wehrli, Suzanne,Cook, James M.
, p. 2169 - 2179 (2007/10/02)
The synthesis of tricyclo4,10>deca-2,5,8-triene (1), 1,10-dimethyltricyclo4,10>deca-2,5,8-triene (3), and tetracyclo1,8.04,8>tetradeca-2,5,13-triene (4) has been accomplished via the reaction of 1,2-dicarbonyl compounds with di-tert-butyl 3-oxoglutarate (Weiss reaction).Condensation of glyoxal 5a with di-tert-butyl 3-oxoglutarate (6b) gave the tetra-tert-butyl cis-dioxobicyclooctane-2,4,6,8-tetracarboxylate 7b in 93percent yield.This bisenol 7b was converted into the bisenol ether 9b regiospecifically (90percent yield).This transformation was followed by monoalkylation (KH, allyl iodide; -58 deg C) and hydrolysis to generate 2-allyl-cis-bicyclooctane-3,7-dione in 90percent overall yield from 9b.The mixture of epimiric 2-allyl-3,7-diones 11a,b was transformed (O3; DMS) into the mixture of epimiric aldehydes 12a,b.This process was followed by aldol cyclization (2 N HCl, THF) to provide the diastereomeric mixture of of endo-(13a) and exo-(13b) triquinane monols in 85percent yield.Reduction of 13a,b with borane-THF (0 deg C) generated the stereoisomeric mixture of triols 14a,b which were subjected to an HPMA-mediated dehydration sequence to provide triquinacene (1), accompanied by small amounts of isotriquinacene.The mixture of trienes were converted into pure 1 by exposure to p-TSA in methylene chloride-pentane.Substitution of biacetyl (5b) for glyoxal 5a in the Weiss reaction, followed by the analogous steps detailed in the synthesis of 1, provided 1,10-dimethyltriquinacene (3).In addition, the synthesis of 1,10-cyclohexanotriquinacene (4), another centro-substituted triquinacene, has been accomplished by substitution of cyclohexane-1,2-dione (23) for 5a in the condensation, followed by the same sequence of reactions presented above for 1 and 3.
REACTION OF DIMETHYL SODIO-3-KETOGLUTARATE WITH GLYOXAL AND SUBSTITUTED GLYOXALS; FIRST EXPEDITIOUS PREPARATION OF BICYCLOOCTANE-3,7-DIONE; SYNTHESIS AND CRYSTAL STRUCTURE OF 5,7-DIHYDROXY-4-METHOXYCARBONYL-3-PHENYL-1-INDANONE
Bertz, Steven H.,Rihs, G.,Woodward, R.B.
, p. 63 - 70 (2007/10/02)
A simple and efficient two-step preparation of bicyclooctane-3,7-dione starting from the sodium enolate of dimethyl 3-ketoglutarate and glyoxal is described.This is an unprecedented case in which a condensation reaction of glyoxal is more successful under vigorous conditions (refluxing methanol) than under much milder ones (buffered water at ambient temperature).The major product (after hydrolysis-decarboxylation) from the analogous sequence with phenylglyoxal is 5,7-dihydroxy-4-methoxycarbonyl-3-phenyl-1-indanone, the result of a Dieckmann reaction in addition to the Michael and aldol reactions.Only the latter two occur in aqueous buffers, where the product after hydrolysis-decarboxylation is 1-phenylbicyclooctane-3,7-dione.The X-ray crystal structure of the indanone reveals a novel hydrogen bonding phenomenon.
