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1.
2.
Giuseppe Guanti Luca Banfi Enrica Narisano Carlo Scolastico 《Tetrahedron letters》1984,25(41):4693-4696
threo-α-Dibenzylamino-?-hydroxyesters (2) have been synthesised with high diastereoselectivity through the NaBH4 reduction of α-dibenzylamino-β-oxoesters (4) and then tranformed into threo-α-amino-β-hydroxyacids. 相似文献
3.
This paper describes the synthesis of a bicyclic beta-amino acid scaffold in both pure enantiomeric forms and its application as chiral auxiliary in an intramolecular version of the Ugi multicomponent reaction (U-5C-4CR) to prepare alpha-amino acid derivatives of both D- and L-series in a straightforward and very stereoselective manner. The mild conditions required for the Ugi condensation and for the removal of the chiral auxiliary make this method very attractive to prepare a wide range of differently structured N-alkylated and unalkylated amino acid derivatives. 相似文献
4.
Stefano Banfi Fernando Montanari Silvio Quici Gaguik Torossian 《Journal of inclusion phenomena and macrocyclic chemistry》1992,12(1-4):159-173
Reaction rates of alkene epoxidations, promoted by aqueous NaOCl and catalyzed by Mn(III)-tetrakis(2,6-dichlorophenyl)porphyrin chloride1 (P) in the presence of a lipophilic axial ligand (L) (e.g.N-hexylimidazole) and carried out under H2O/CH2Cl2 two phase conditions at 0°C, are strongly enhanced by lowering the pH of the aqueous phase from 12.7 to 9.5. Under these conditions, a further relevant increase in the reaction rates can be achieved by adding phase-transfer catalysts (PT), e.g. quaternary ammonium salt 3, lipophilic crown ether4 or cryptand5, provided that the amount of L is very small (L/P=1 for very reactive alkenes, e.g. cyclooctene, and 10 for poorly reactive ones, e.g. 1-dodecene). In the case of cyclooctene epoxidation, the use of 0.006–0.03 mol. equiv. of PT completes the reaction in 1–10 min., the initial rates being up to 600 turnovers/min. with (2.2.2,C10) cryptand. In the absence of the axial ligand, the quaternary ammonium salt3 and cryptand5 show an inhibitory effect. Such an effect is due to the formation of the poorly reactive Mn(P)CI species, by Cl– extraction to the organic phase. However, dibenzo crown ether 4 does not show this effect. In the presence of 4, and with L/P =1, the 1-dodecene epoxidation reaches 94% in 1 min. The unique behavior of crown ethers can be explained by their ineffectiveness in extracting alkali chlorides, providing a very low concentration of Cl– in the organic phase and thus avoiding the Mn(III)-porphyrin deactivation.This paper is dedicated to the memory of the late Dr C. J. Pedersen. 相似文献
5.
The synthesis of the methyl esters of optically pure trans and cis 4-guanidinocyclohexylglycine as rigid analogues of D-arginine methyl ester are described. 相似文献
6.
7.
Luca Banfi 《Tetrahedron letters》2004,45(22):4221-4223
The new simplified dynemicin analogue 16 was prepared enantio- and diastereoselectively in 17 steps starting from monoacetate (S) 7. It is equipped with a side arm containing a protected primary alcoholic function (`handle'), which can be used for conjugation with DNA-complexing agents or for devising new types of trigger. 相似文献
8.
Aldo Banfi Alberto Sala P. Angelo Soresinetti Giovanni Russo 《Journal of heterocyclic chemistry》1990,27(2):215-219
The preparation of new imidazole derivatives containing a carboxylic moiety such as succinic, adipic or benzoic into the side chain, is reported starting from the suitable imidazole intermediates. 相似文献
9.
10.
De Moliner F Banfi L Riva R Basso A 《Combinatorial chemistry & high throughput screening》2011,14(9):782-810
The reaction of isocyanides with electron deficient alkynes has been first reported in 1969, about ten years after the first reports on the famous Ugi four component reaction. However it took about thirty years to realise that the zwitterionic intermediate originating from interaction of the two species could be trapped by a third component, thus giving the start to a novel class of isocyanide-based multicomponent reactions. From that first report dated 1996 there has been an ongrowing interest that has produced, so far, about 150 distinct scientific papers. This review is aimed at rationalising and cathegorising these reports and at offering an overview of all the possible applications of this novel methodology. 相似文献