Preparation of Benzolactams by Pd(OAc)2-Catalyzed Direct Aromatic Carbonylation
摘要:
We developed a new method for Pd(II)-catalyzed direct aromatic carbonylation in a phosphine-free catalytic system using Pd(OAc)2 and Cu(OAc)2 in an atmosphere of CO gas containing air. The carbonylation proceeded with ortho-palladation, inducing a remarkable site selectivity to afford a variety of five- or six-membered benzolactams from secondary omega-arylalkylamines, such as N-alkylbenzylamines or N-alkylphenethylamines.
Separation of Ring Polar and Resonance Effects on the Rate Constants for Uncatalyzed N-Arylidenepropylamine Formation in Methanol
作者:Jean Toullec、Didier Milin
DOI:10.1021/jo00089a033
日期:1994.5
Rate constants are reported for the reaction of a series of 19 ring-substituted benzaldehydes with propylamine in methanol and in O-d-methanol at different temperatures and of three of them with 2-methoxyethylamine and 2,2-dimethoxyethylamine. The large direct solvent kinetic isotope effects (KSIE) (2.1-2.9), as well as the Delta H* (4.7-7.6 kcal mol(-1)) values vary smoothly with substituent. Delta S* (ca. -45 cal mol(-1) K-1) is almost independent of substituent. These data indicate that there in no change in the rate-limiting step, and since the large KSIE and \Delta S*\ can be related to significant solvation of the leading OH- group at the transition state, they agree with a mechanism involving cu-amino alcohol formation in a fast preequilibrium followed by rate-limiting OH- detachment yielding iminium ions. When corrected for parallel hemiacetal formation, the second-order rate constants are accounted for by the Young-Jencks equation with p(n) = 0.08 and p(r) = 0.57, this equation allowing a separation of the direct resonance effects from the polar effects of the substituted ring. The very low p(n) value indicates that the polar effects for the rate-limiting OH- detachment are almost compensated by those on the constant of the alpha-amino alcohol-formation preequilibrium. In contrast, the relatively large p(r) coefficient, which means that the overall rate constants depend almost exclusively on resonance, is due to predominance of the direct resonance effects on the preequilibrium. The KSIE and Delta S* data, as well as the beta(nucl) parameters (close to unity) observed when the reacting amine was changed (slopes of the straight lines obtained by plotting the logarithm of the rate constants vs the pK(a) of the ammonium ions) favor a late transition state. In contrast, the low p(r) value for the rate-limiting step (ca. -0.5) shows that the transition state is not iminium ion-like.
Synthesis of Novel 2-Alkoxy-3-amino-3-arylpropan-1-ols and 5-Alkoxy-4-aryl-1,3-oxazinanes with Antimalarial Activity
作者:Matthias D’hooghe、Stijn Dekeukeleire、Karen Mollet、Carmen Lategan、Peter J. Smith、Kelly Chibale、Norbert De Kimpe
DOI:10.1021/jm9002632
日期:2009.7.9
A variety of novel syn-2-alkoxy-3-amino-3-arylpropan-1-ols was prepared through LiAlH4-promoted reductive ring-opening of cis-3-alkoxy-4-aryl-beta-lactams in Et2O. The latter gamma-aminoalcohols were easily converted into cis-5-alkoxy-4-aryl-1,3-oxazinanes using formaldehyde in THE Both series of compounds were evaluated against a chloroquine sensitive strain of Plasmodium falciparum (D10), revealing micromolar potency for almost all representatives. Eleven compounds exhibited antimalarial activity with IC50 values of <= 30 mu M, and the majority of these compounds did not show cytotoxicity at the concentrations tested.
Preparation of Benzolactams by Pd(OAc)<sub>2</sub>-Catalyzed Direct Aromatic Carbonylation
We developed a new method for Pd(II)-catalyzed direct aromatic carbonylation in a phosphine-free catalytic system using Pd(OAc)2 and Cu(OAc)2 in an atmosphere of CO gas containing air. The carbonylation proceeded with ortho-palladation, inducing a remarkable site selectivity to afford a variety of five- or six-membered benzolactams from secondary omega-arylalkylamines, such as N-alkylbenzylamines or N-alkylphenethylamines.
Mannich‐Type Reactions of Alkylzinc Reagents
作者:Marine Pinaud、Emilie Plantiveau、Eric Huet、Erwan Le Gall、Marc Presset
DOI:10.1002/ejoc.202300572
日期:2023.8.21
The addition of alkylzinc halides to imines has been studied under different conditions. Whereas Mannich-type reactions with sulfonyl imines occurs upon simple heating, the use N-alkyl imines required an additional activation: the use of acetyl chloride led to the preparation of N-acyl tertiary amines whereas trimethylsilyl chloride afforded a direct access to unprotected secondary amines.