Hetero Diels-Alder cyclocondensation of F-alkyl aldehydes with the Danishefsky diene
摘要:
The heterocyclocondensation of F-alkylated aldehydes R-F(CH2)(n)CHO with Danishefsky's diene depends on the mutual vicinity of the carbonyl and the F-alkyl chain: when n = 4 it leads to 4-oxo pyr-2-ene 4, but when n = 0 the trimethylsilyloxypyrene 3 without methoxy elimination only results. (C) 1997 Published by Elsevier Science Ltd.
Synthesis of Per(poly)fluoroalkyl aldehydes RF(CH2)nCHO
作者:Laurence Le´veˆque、Maurice Le Blanc、Raphae¨l Pastor
DOI:10.1016/s0040-4039(98)02029-2
日期:1998.11
We report the preparation of polyfluoroalkyl aldehydes RF(CH2)nCHO in high yields by direct oxidation of polyfluoroalkyl alcohols; the Swern oxidation, pyridinium chlorochromate and Dess-Martinperiodinane are used and compared
New anionic glycophospholipids with two perfluorocarbon or two hydrocarbon or mixed hydrophobic chains
作者:Frédéric Guillod、Jacques Greiner、Jean G. Riess
DOI:10.1016/0009-3084(95)02492-2
日期:1995.11
Novel amphiphilic anionic sugar phosphates esterified by various hydrophobic double-chain tails were synthesized. They differ primarily by the design of their hydrophobic tail. Amphiphile 12a derives from phosphogalactose and has two perfluoroalkylated hydrophobic chains; 12b has a pentenyloxy spacer between the mixed hydrocarbon/fludrocarbon double-chain and the same head group; 12c and 14c are galactose and glucose derivatives with two hydrocarbon tail chains. All were prepared through a three-step H-phosphonate route: reaction of the hydrophobic double-chain alcohol on phosphorus trichloride (27-60%), followed by the addition of the appropriately protected sugar, by oxidation (50-81%), and finally by deprotection of the sugar (58-95%). The starting alcohols were prepared through conventional reactions. Their synthesis was however, difficult, essentially as a result of lesser reactivity, and of low solubility of some of the intermediates related to the presence of the bulky, strongly hydrophobic chains. Preliminary biocompatibility assays indicate a reduction in hemolytic activity by increasing the number of fluorinated chains or by increasing the total length, hence the hydrophobicity of the amphiphile. Acute toxicity tests indicate maximum intravenously tolerated doses in mice of ca. 500 mg/kg body weight for 12a and 12b.
Asymmetric heterocyclocondensation of polyfluorinated aldehydes catalysed by a chiral titanium(IV) complex
作者:Laurence Lévêque、Maurice Le Blanc、Raphaël Pastor
DOI:10.1016/s0040-4039(00)00762-0
日期:2000.6
The Binol/Ti(OiPr)(4) chiral titanium complex catalyses the asymmetric cyclocondensation of polyfluoroalkylaldehydes with the Danishefsky's diene leading to chiral polyfluoroalkyl dihydropyrenones with high enantiomeric excesses. (C) 2000 Published by Elsevier Science Ltd.
A convenient access to (F-alkyl)alkanals
作者:Gianluca Pozzi、Silvio Quici、Ian Shepperson
DOI:10.1016/s0040-4039(02)01290-x
日期:2002.8
Aldehydes R-F(CH2)(m)CHO (R-F=n-CnF2n+1) have been prepared in good yields by oxidation of the corresponding alcohols using inexpensive and safe oxidants such as phenyliodine (III) diacetate and trichloroisocyanuric acid in the presence of 2,2.6,6-tetramethyl-1-piperidinyloxyl free-radical (TEMPO) as a catalyst. (C) 2002 Elsevier Science Ltd. All rights reserved.