The reaction of dialkyl acetals derived from α,β-unsaturated aldehydes with Grignard reagents using TiCl4in THF afforded the cross coupling products, allyl ethers, in high yields. The TiCl4-promotedreaction of alkyl 2,4-dichlorophenyl acetals, synthesized from 3,4-dihydro-2H-pyran or ethyl vinyl ether and 2,4-dichlorophenol, with Grignard reagents in THF at low temperature afforded the corresponding
Piperidine and Azetidine Formation by Direct Cyclization of Diols with N-Nonsubstituted Sulfonamide under the Mitsunobu Conditions Utilizing (Cyanomethylene)tributylphosphorane (CMBP) and Its Application to the Synthesis of Lupinine
our studies on the Mitsunobu chemistry, diethylazodicarboxylate (DEAD)-PPh3 and our new azodicarboxamide reagents, e.g., N,N,N’,N’-tetramethylazodicarboxamide (TMAD)-PBu3 could not promote alkylation of N-nonsubstituted sulfonamides such as TsNH2, because the amide reacted with PPh3 or PBu3 to form triphenylor tributylphosphine tosylimide (TsN=PR3) under the reaction conditions. Furthermore, the same
Removal of benzotriazole moiety from 2-[2-aryl-2-(benzotriazol-1-yl)ethyl]tetrahydro-2H-pyrans and 2-[2-aryl-2-(benzotriazol-1-yl)ethyl]-5-(methyl)tetrahydrofurans using lithium naphthalene radical anion
作者:Yoon Ho Kang、Kyongtae Kim
DOI:10.1016/s0040-4020(99)00120-9
日期:1999.4
naphthalenides (6b), 2-[2-aryl-2-(benzotriazol-1-yl)ethyl]tetrahydro-2H-pyrans (4), and 2-[2-aryl-2-(benzotriazol-1-yl)ethyl]-5-(methyl)tetrahydrofurans (5), and 1-(benzotriazol-1-yl)-1,2-diphenylethane (7) were prepared. The reactions of 4 with 6a in THF at room temperature gave 2-(2-arylethyl)tetrahydro-2H-pyrans (12) in 45 to 62 % yields along with benzotriazole and naphthalene. In addition, 2-(benzoyleth
gamma- and delta-Lactones 5, 6, 13, 14, 15 and 16 were synthesized via baker's yeast reduction of the corresponding keto acids 3 ,4 and 9-12. The enantioselectivity of the reduction is strongly dependent on the nature of the keto acid: the delta-lactones were always obtained in an ee% higher than the gamma-lactones and ranging from 70% to 100%.
Acetylenic Reactions of 2-(Phenylethynyl)tetrahydropyran<sup>1</sup>