7028-47-9Relevant articles and documents
Hydroxylated HMPA enhances both reduction potential and proton donation in SmI2 reactions
Halder, Sandipan,Hoz, Shmaryahu
, p. 2682 - 2687 (2014)
HMPA is known to increase the reduction potential of SmI2. However, in many cases, the transferred electron returns from the radical anion of the substrate back to the Sm3+. This could be avoided by an efficient trapping of the radical anion: e.g., by protonation. However, bimolecular protonation by a proton donor from the bulk may be too slow to compete with the back electron transfer process. An efficient unimolecular protonation could be achieved by using a proton donor which complexes to SmI2, in which case the proton is unimolecularly transferred within the ion pair. A derivative of HMPA in which one of the methyl groups was substituted by a CH2CH2OH unit was synthesized. Cyclic voltammetry studies have shown that it resembles HMPA in its ability to enhance the reduction potential of SmI2, and reactivity studies show that it has also efficient proton shift capabilities. The various aspects of this additive were examined in the reactions of SmI2 with three substrates: benzyl chloride, methyl cinnamate, and anthracene.
Samarium-induced reductive dimerization of methyl cinnamate: Synthesis of 2,8-diamino chrysene
Banik, Bimal K.,Venkatraman,Banik, Indrani,Basu, Manas K.
, p. 4737 - 4739 (2004)
Samarium metal-induced reductive dimerization of methyl cinnamate was performed for the first time. A unique role for aluminum was indicated in the dimerization reaction. The intermediate adipate ester was converted to 2,8-diamino chrysene.
Cathodic reductive coupling of methyl cinnamate on boron-doped diamond electrodes and synthesis of new neolignan-type products
Kojima, Taiki,Obata, Rika,Saito, Tsuyoshi,Einaga, Yasuaki,Nishiyama, Shigeru
supporting information, p. 200 - 203 (2015/02/19)
The electroreduction reaction of methyl cinnamate on a boron-doped diamond (BDD) electrode was investigated. The hydrodimer, dimethyl 3,4-diphenylhexanedioate (racemate/meso = 74:26), was obtained in 85% yield as the major product, along with small amounts of cyclic methyl 5-oxo-2,3-diphenylcyclopentane-1-carboxylate. Two new neolignan-type products were synthesized from the hydrodimer.
Csp3-Csp3 homocoupling reaction of benzyl halides catalyzed by rhodium
Sato, Kazuyuki,Inoue, Yuichi,Mori, Tomohisa,Sakaue, Atsushi,Tarui, Atsushi,Omote, Masaaki,Kumadaki, Itsumaro,Ando, Akira
supporting information, p. 3756 - 3759 (2014/08/05)
A highly reactive alkylrhodium complex was formed from Me2Zn and RhCl(PPh3)3 and effectively catalyzed a Csp 3-Csp3 homocoupling reaction of benzyl halides. A Csp 3-Csp3 coupling reaction using Rh catalyst has not been reported up to now. The reaction proceeded under very mild conditions and gave the corresponding homocoupling products even if they had reactive substituents such as an uncovered formyl or hydroxymethyl group.
Stereoselective hydrocoupling of cinnamic acid esters by electroreduction: Application to asymmetric synthesis of hydrodimers
Kise, Naoki,Iitaka, Shumei,Iwasaki, Keisuke,Ueda, Nasuo
, p. 8305 - 8315 (2007/10/03)
The electroreduction of Ar-substituted methyl cinnamates in acetonitrile gave all-trans cyclized hydrodimers stereoselectively (58-90% de). In all cases, small amounts (2-symmetric dl-3,4-diaryladipic acids and trans-3,4-diarylcyclopentanones. The chiral auxiliary [(1R)-exo]-3-exo-(diphenylmethyl)borneol, prepared from (1R)-(+)-camphor, was highly effective for the stereoselective hydrocoupling of its cinnamates by electroreduction. From the resulting hydrodimers, (3R,4R)-3,4-diaryladipic acid esters and (3R,4R)-3,4-diarylhexane-1,6-diols were synthesized in 87-95% ee.
Stereoselective hydrocoupling of [(1R)-exo]-3-exo-(diphenylmethyl)bornyl cinnamates by electroreduction
Kise, Naoki,Iwasaki, Keisuke,Tokieda, Naohiko,Ueda, Nasuo
, p. 3241 - 3244 (2007/10/03)
Equation presented The chiral auxiliary [(1R)-exo]-3-exo-(diphenylmethyl)borneol, synthesized from (1R)-(+)-camphor in three steps, was highly effective for the stereoselective hydrocoupling of its cinnamates by electroreduction. From the resulting hydrod
Electrochemical methoxylation of cinnamic acid and its derivatives
Il'chibaeva,Kagan,Tomilov
, p. 1592 - 1595 (2007/10/03)
Electrochemical methoxylation of cinnamic acid is accompanied by decarboxylation and yields 1,1,2-trimethoxy-2-phenylethane through formation of γ-truxillic acid in the initial stage. Under the same conditions methyl cinnamate and cinnamamide give rise to
The influence of solvent on the mechanism and stereochemistry of electrohydrodimerization. The reduction of cinnamic acid Esters in methanol
Fussing, Ingrid,Hammerich, Ole,Hussain, Abid,Nielsen, Merete Folmer,Utley, James H. P.
, p. 328 - 337 (2007/10/03)
The kinetics and mechanisms of reactions following electrochemical reduction of members of a series of cinnamic acid esters, Ph-CH=CH-COOR, R=alkyl or aryl, in methanol (MeOH) have been studied. The results are compared with those previously obtained for reduction of the same compounds in N, N-dimethylformamide (DMF). The change from DMF to MeOH gives rise to important differences which are related to the higher acidity and the hydrogenbond donating capabilities of MeOH. The changes include: (i) anodic shifts of the formal reduction potentials, in MeOH, by 80-130 mV; (ii) increased rates of reaction of the radical anions in MeOH by 2-3 orders of magnitude; (iii) in contrast with clean 1 F processes for the entire series in DMF, reduction in MeOH gave a 1 F process for the aryl cinnamates and a ≈ 1.5 F process for the alkyl cinnamates; (iv) the products of preparative scale reduction of methyl cinnamate in MeOH were a mixture of the saturated ester (2 F) and the meso and (±) isomers of the linear hydrodimer (1 F), whereas reduction in DMF gave exclusively the cyclized 1 F product, all-trans-2-methoxycarbonyl-3,4-diphenylcyclopentanone [corresponding to (±) coupling]; (v) the stereochemistry of the product of coupling changes from exclusively (±), in DMF, to equal amounts of meso and (±) in MeOH. The changes may be rationalized in a mechanism which crucially involves initial formation of a radical anion hydrogen-bonded (at the carbonyl oxygen) to MeOH. Linear sweep voltammetric experiments reveal an important dependence of reaction order upon the type of ester reduced, which is strong evidence of competition between dimerization of the hydrogen-bonded radical anion in a rate-determining second-order reaction (favored for the aryl esters) and rate-determining protonation in a first-order reaction of the carbonyl oxygen (favored for alkyl esters). It is also shown that the neutral radicals formed by protonation of the radical anions at oxygen are more difficult to reduce than the parent ester and may either dimerize (1 F) or tautomerize to the more easily reduced carbon protonated radical (2F). The change in mechanism and stereoselectivity of electroreduction on going from DMF to MeOH electrolyte seems to be general for hydrodimerizations. Acta Chemica Scandinavica 1998.
Photoinduced electron transfer reactions of cyclopropanone acetal with conjugated enones in the presence of a redox-type photosensitizer
Abe, Manabu,Nojima, Masatomo,Oku, Akira
, p. 1833 - 1836 (2007/10/03)
Photoreactions of the cyclopropanone acetal 1 with conjugated enones 2 in the presence of phenanthrene or pyrene as a redox-type photosensitizer gave the corresponding cross-coupling product 3 or mixtures of 3 with 5 in good yields together with the β-carbonyl radical-dimer 4.
Stereoselectivity and mechanism in the electrohydrodimerisation of esters of cinnamic acid
Fussing, Ingrid,Guellue, Mustafa,Hammerich, Ole,Hussain, Abid,Nielsen, Merete Folmer,Utley, James H. P.
, p. 649 - 658 (2007/10/03)
Rate constants (kobs) and reaction orders have been determined for the cathodic reduction in DMF solution of 11 cinnamiic acid esters including some derived from chiral alcohols and a dicinnamate derived from trans-cyclohexane-1,2-diol.The cinn
