2-METHYL-3-HYDROXY-4H-pyran-4-one is prepared by contacting 1(2-furyl)-1-ethanol in aqueous solution with two equivalents of a halogen oxidant at room temperature and then heating until the hydrolysis of the formed 4-halo-dihydropyran intermediate is substantially complete. Other valuable related gamma-pyrones are prepared in analogous manner from appropriate alcohols.
Gold Catalysis: Biarylphosphine Ligands as Key for the Synthesis of Dihydroisocoumarins
作者:A. Stephen K. Hashmi、Benjamin Bechem、Annette Loos、Melissa Hamzic、Frank Rominger、Hassan Rabaa
DOI:10.1071/ch13552
日期:——
A gold-catalyzed phenol synthesis was successfully used in the synthesis of dihydroisocoumarins for the first time. A large number of gold(i) complexes were prepared and tested; only complexes based on the biarylphosphine motif were successful.
Intermediates for the preparation of gamma-pyrones
申请人:Pfizer Inc.
公开号:US04387235A1
公开(公告)日:1983-06-07
2-methyl-3-hydroxy-4H-pyran-4-one is prepared by contacting 1(2-furyl)-1-ethanol in aqueous solution with two equivalents of a halogen oxidant at room temperature and then heating until the hydrolysis of the formed 4-halo-dihydropyran intermediate is substantially complete. Other valuable related gammapyrones are prepared in analogous manner from appropriate alcohols.
3,4-Dihalo-tetrahydrophyran-5-one useful as intermediates for the
申请人:Pfizer Inc.
公开号:US04368331A1
公开(公告)日:1983-01-11
(2-methyl-3-hydroxy-4h-pyran-4-one is prepared by contacting 1(2-furyl)-1-ethanol in aqueous solution with two equivalents of a halogen oxidant at room temperature and then heating until the hydrolysis of the formed 4-halo-dihydro-pyran intermediate is substantially complete. Other valuable related gamma-pyrones are prepared in analogous manner from appropriate alcohols.
Intramolecular Diels-Alder Reaction of Furans with Allenyl Ethers: High Effect of the Chain Length on the Structure and Reactivity of the Cycloadducts
作者:Hsien-Jen Wu、Shie-Hsiung Lin、Chu-Chung Lin
DOI:10.3987/com-94-6675
日期:——
The structure and reactivity of the cycloadducts of the title reaction were found to be highly dependent on the chain length between the furan diene and the allenyl ether dienophile. Reaction of the propargyl ether (2) with t-BuOK in t-BuOH at 85-degrees-C for 3 h gave a mixture of the cycloadducts (3) and (4) in 90% yield, which were transferred to the benzo derivatives (5), (6) and (7). Treatment of the propargyl ether (8) with t-BuoK in t-BuOH at 85-degrees-C for 5 h gave the products (9) and (10) in a ratio of 8:1 in 65% yield, no detectable amount of the cycloadduct (8b) was obtained. Refluxing of the propargyl ether (13) with t-BuOK in t-BuOH at 85-degrees-C for 4 h gave the allenyl ether (14). Heating 14 in DMSO at 15-degrees-C for 12 h still did not give 15.