• Bulletin of the Korean Chemical Society
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• 제27권11호
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• pp.1873-1876
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• 2006

• Bulletin of the Korean Chemical Society
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• 제11권6호
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• pp.516-520
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• 1990

The product distribution obtained by the addition of hydride of $-CR_2CN$ (R = H and Me) to (disubstituted benzene)-$FeCp^+$ is studied. The formation of the substituted arene from ${\eta}^5$-cyclohexadienyl-${\eta}^5$-cyclopentadienyliron is described.

• Bulletin of the Korean Chemical Society
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• 제33권10호
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• pp.3448-3450
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• 2012

• Bulletin of the Korean Chemical Society
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• 제11권6호
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• pp.481-483
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• 1990

• Bulletin of the Korean Chemical Society
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• 제29권6호
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• pp.1195-1198
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• 2008

Kinetic studies of the additions of benzylamines to a noncyclic dicarbonyl group activated olefin, methyl $\alpha$-acetyl-$\beta$ -phenylacrylates (MAP), in acetonitrile at 30.0 ${^{\circ}C}$ are reported. The rates are lower than those for the cyclic dicarbonyl group activated olefins. The addition occurs in a single step with concurrent formation of the $C_\alpha$ -N and $C_\beta$ -H bonds through a four-center hydrogen bonded transition state. The kinetic isotope effects ($k_H/k_D$ > 1.0) measured with deuterated benzylamines ($XC_6H_4CH_2ND_2$) increase with a stronger electron acceptor substituent ($\delta\sigma$ X > 0) which is the same trend as those found for other dicarbonyl group activated series (1-4). The sign and magnitude of the cross-interaction constant, ρXY, is comparable to those for the normal bond formation processes in the $S_N2$ and addition reactions. The relatively low ${\Delta}H^\neq$ and large negative ${\Delta}S^\neq$ values are also consistent with the mechanism proposed.

• Bulletin of the Korean Chemical Society
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• 제23권2호
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• pp.221-224
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• 2002

Nucleophilic addition reactions of benzylamines (BA; $XC_6H_4CH_2NH_2$) to ethyl-${\alpha}$-cyanocinnamates (ECC;$YC_6H_4CH$=C(CN)COOEt) have been investigated in acetonitrile at $30.0^{\circ}C$. The rate is first order with respect to BA and ECC. The rate is slower than that expected from the additive effect of ${\sigma}^-$ or $R^-$ for the activating groups (CN and COOEt). Natural. bond orbital ${\pi}^{\ast}_{c=c}$ calculations show that the contribution of COOEt group may not be fully effective despite the coplanar molecular structure. The selectivity parameters including the cross-interaction constant (${\rho}_{xy}$ = -0.22) indicate that the addition occurs in a single step. The kinetic isotope effects ($k_H/k_D$=2.5-2.8) involving deuterated BA ($XC_6H_4CH_2ND_2$) nucleophiles and activation parameters (${\Delta}H^{\neq}=4{\sim}6\;kcal\;mol^{-1};{\Delta}S^{\neq}=-45{\sim}-52\;e.u.$) suggest a cyclic transition state in which N-$C_{\alpha}$ and H-$C_{\beta}$ bonds are formed concurrently.

• Bulletin of the Korean Chemical Society
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• 제24권2호
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• pp.193-196
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• 2003

Nucleophilic addition reactions of benzylamines $(XC_6H_4CH_2NH_2)$ to benzylidene Meldrum's acids (BMA; $YC_6H_4CH=C(COO)_2C(CH_3)_2$) have been investigated in acetonitrile at 20.0 ℃. The rates of addition are greatly enhanced due to the abnormally high acidity of Meldrum's acid. The magnitudes of the Hammett $({\rho}_X\;and\;{\rho}_Y)$ and Bronsted $({\rho}_X$)$ coefficients are rather small suggesting an early transition state. The sign and magnitude of the cross-interaction constant, ${\rho}_{XY}$ (= -0.33), and kinetic isotope effects $(k_H/k_D\;{\stackrel}{~}{=}\;1.5-1.7)$ involving deuterated benzylamine nucleophilies $(XC_6H_4CH_2ND_2)$ are indicative of hydrogen-bonded cyclic transition state. The activation parameters, ${\Delta}H^{\neq}\;{\stackrel}{~}{=}\;4\;kcal\;mol^{-1}\;and\;{\Delta}S^{\neq}\;{\stackrel}{~}{=}\;-37\;e.u.$, are also in line with the proposed mechanism.

• 대한화학회지
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• 제26권6호
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• pp.407-413
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• 1982

3,4-methylenedioxyphenylmethylene malononitrile에 대한 cysteine의 친핵성 첨가반응 속도를 측정하여 염기성 및 산성용액에서의 반응메카니즘을 제안하였고 넓은 pH범위에서 잘 맞는 반응속도식을 구했다. 이 반응속도식으로 부터, pH 9.0 이상에서는 hydroxide ion 농도에만 비례하고, pH 6.0 이하에서는 cysteine의 중성분자만이 첨가하며, pH 7~9.0에서는 cysteine 중성분자와 그의 음이온이 경쟁적으로 첨가됨을 알 수 있었고 첨가되는 cysteine 중성분자와 음이온의 비도 계산할 수 있었다.

• 대한화학회지
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• 제38권12호
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• pp.908-914
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• 1994

5원자 고리형 ${\beta}$-keto ester와 phenylalkylamine의 탈수축합으로 얻은 enamine A의 oxalyl화 및 물이나 메탄올 부가에 의하여 octahydro-2,3-dioxo-cyclopenta[b]-pyrrole-3a-carboxylate의 6a-hydroxy- 및 6a-methoxy-유도체(1~6)를 합성하였다. 헤테로 고리의 형성은 불안정한 N-acyliminium(B)체를 경유하여 일어나며, 안정한 부가체 C (1∼6)는 endo-ene형 pyrrolinium B에 친핵체를 부가하여 얻을 수 있었다.

• Bulletin of the Korean Chemical Society
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• 제27권5호
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• pp.733-738
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• 2006

Nucleophilic addition reactions of p-substitutedbenzylamines $(XC _6H_4CH _2NH _2)$ to $\alpha$-phenyl-$\beta$-thiophenyl-acrylonitriles ($YC _4SH _2CH=C(CN)C_6H_4$Y') have been studied in acetonitrile at 25.0, 30.0, and 35.0 ${^{\circ}C}$. The reactions take place in single step in which the $C_\beta$ -N bond formation and proton transfer to $C_\alpha$ of $\alpha$-phenyl-$\beta$-thiophenylacrylonitriles occur concurrently with four-membered cyclic transition structure. These mechanistic conclusions are drawn based on (i) the large negative $\rho$x and large positive $\rho$Y' values and also large magnitude of $\rho$X, (ii) the negative sign and large magnitude of the cross-interaction constants ($\rho$XY), (iii) the normal kinetic isotope effects ($k_H/k_D$ > 1.0), and (iv) relatively low $\Delta H ^\neq$ and large negative $\Delta S ^\neq$ values.