62497-24-9Relevant articles and documents
Application and scope of Schreiber's gold(I)-catalyzed α-pyrone synthesis to ring a aromatic podolactones
Sánchez-Larios, Eduardo,Giacometti, Robert D.,Hanessian, Stephen
supporting information, p. 5664 - 5669 (2014/11/08)
Schreiber's gold(I)-catalyzed synthesis of α-pyrones was adapted to the total synthesis of a ring A aromatic podolactone, urbalactone. The scope of the acetylenic ester partner in the formation of α-pyrones was studied. The total synthesis features, as ke
Total synthesis of (+)-lithospermic acid by asymmetric intramolecular alkylation via catalytic C-H bond activation
O'Malley, Steven J.,Tan, Kian L.,Watzke, Anja,Bergman, Robert G.,Ellman, Jonathan A.
, p. 13496 - 13497 (2007/10/03)
The total synthesis of (+)-lithospermic acid is described. The efficient synthesis features an asymmetric alkylation via C-H bond activation to assemble the dihydrobenzofuran core of the natural product. This was accomplished via a chiral imine-directed C
Preparation of Arylpropiolate Esters from Trichlorocyclopropenium Cation and Elaboration of the Esters to Unsymmetrical 1,4-Pentadiyn-3-ones and Unsymmetrical Tellurapyranones
Wadsworth, Donald H.,Geer, Susan M.,Detty, Michael R.
, p. 3662 - 3668 (2007/10/02)
The addition of aromatic compounds including thiophene, naphthalene derivatives, and some benzene derivatives to trichlorocyclopropenium cation gave nearly quantitative yields of 1-aryl-2,3,3-trichlorocyclopropenes.Alcoholysis of the cyclopropene derivatives gave either arylpropiolate esters or arylpropiolate orthoesters (in the presence of added amine base).The arylpropiolates can be converted to unsymmetrical 1,4-pentadiyn-3-ones by two different approaches.The first approach involved reduction of the arylpropiolate esters with diisobutylaluminum hydride to give the corresponding propargyl alcohol.Pyridinium chlorochromate or manganese dioxide oxidation of the alcohol gave the propargyl aldehydes.Addition of a lithium acetylenide gave a 1,4-pentadiyn-3-ol, which could then be oxidized to the 1,4-pentadiyn-3-one with 10percent chromic acid or manganese dioxide.The second pathway used a Lewis acid mediated coupling of a propargylic acid chloride with a (trimethylsilyl)acetylene to give the 1,4-pentadiyn-3-ones directly.The coupling of 2-thiophenepropiolic acid chloride gave the product of HCl addition to the expected 1,4-diynone.The regiochemistry of addition was determined to be chloride addition to the thiophene-bearing triple bond on the basis of 1H NMR studies.The diynones were converted to unsymmetrical 2,6-disubstituted tellura-4H-pyran-4-ones with disodium telluride anion.
