- Preparation of ethyl arylpropiolates from aryl iodides by palladium-catalyzed cross-coupling reaction
-
The palladium-catalyzed cross-coupling reaction of aryl iodides with 3,3,3-triethoxy-1-propyne gave 1-aryl-3,3,3-triethoxy-1-propynes which were converted to the corresponding ethyl arylpropiolates. The arylpropiolates were also synthesized from the cross-coupling reactions of aryl iodides with 2-ethoxycarbonyl-1-ethynylzinc chloride or ethyl (tributylstannyl)propiolate, but the reactions were not generally applicable.
- Sakamoto,Shiga,Yasuhara,Uchiyama,Kondo,Yamanaka
-
-
Read Online
- Preparation of Arylpropiolate Esters from Trichlorocyclopropenium Cation and Elaboration of the Esters to Unsymmetrical 1,4-Pentadiyn-3-ones and Unsymmetrical Tellurapyranones
-
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.
- Wadsworth, Donald H.,Geer, Susan M.,Detty, Michael R.
-
p. 3662 - 3668
(2007/10/02)
-
- REACTION OF ACETYLENIC AND VINYLIC ORGANOLITHIUM REAGENTS WITH TRIETHOXYCARBENIUM TETRAFLUOROBORATE: PREPARATION OF α-ACETYLENIC AND α-ETHYLENIC TRIETHYL ORTHOCARBOXYLATES
-
Acetylenic and vinylic liyhium derivatives react with triethoxycarbenium tetrafluoroborate to give α-unsaturated triethyl orthocarboxylates.
- Picotin, G.,Miginiac, Ph.
-
p. 249 - 254
(2007/10/02)
-