4403-14-9Relevant academic research and scientific papers
Titanocene dichloride complexes bonded to carbosilane dendrimers via a spacer of variable length - Molecular dynamics calculations and catalysis of allylic coupling reactions Metallodendrimers Special Issue
Stra?ák, Tomá?,Jaroschik, Florian,Maly, Marek,?ermák, Jan,Sykora, Jan,Fajgar, Radek,Karban, Jind?ich,Harakat, Dominique
, p. 137 - 146 (2014)
Carbosilane metallodendrimers of the first generation Si{CH 2CH2CH2SiMe2CH2CH 2SiMe2(CH2)nC5H 4TiCl2C5H5/s
Enantioselective Reductive Homocoupling of Allylic Acetates Enabled by Dual Photoredox/Palladium Catalysis: Access to C2-Symmetrical 1,5-Dienes
Zhang, Hong-Hao,Tang, Menghan,Zhao, Jia-Jia,Song, Changhua,Yu, Shouyun
supporting information, p. 12836 - 12846 (2021/08/30)
Transition-metal-catalyzed reductive coupling reactions have emerged as powerful protocols to construct C-C bonds. However, the development of enantioselective C(sp3)-C(sp3) reductive coupling remains challenging. Herein, we report a highly regio-, diastereo-, and enantioselective reductive homocoupling of allylic acetates through cooperative palladium and photoredox catalysis using diisopropylethylamine or Hantzsch ester as a homogeneous organic reductant. This straightforward protocol enables the stereoselective construction of C(sp3)-C(sp3) bonds under mild reaction conditions. A series of C2-symmetrical chiral 1,5-dienes were easily prepared with excellent enantioselectivities (up to >99% ee), diastereoselectivities (up to >95:5 dr), and regioselectivities (up to >95:5 rr). The resultant chiral 1,5-dienes can be directly used as chiral ligands in asymmetric synthesis, and they can be also transformed into other valuable chiral ligands.
Luminescent tungsten(vi) complexes as photocatalysts for light-driven C-C and C-B bond formation reactions
Chan, Kaai-Tung,Che, Chi-Ming,Du, Lili,Liu, Yungen,Phillips, David Lee,To, Wai-Pong,Tong, Glenna So Ming,Wu, Liang-Liang,Yu, Daohong
, p. 6370 - 6382 (2020/07/15)
The realization of photocatalysis for practical synthetic application hinges on the development of inexpensive photocatalysts which can be prepared on a large scale. Herein an air-stable, visible-light-absorbing photoluminescent tungsten(vi) complex which can be conveniently prepared at the gram-scale is described. This complex could catalyse photochemical organic transformation reactions including borylation of aryl halides, such as aryl chloride, reductive coupling of benzyl bromides for C-C bond formation, reductive coupling of phenacyl bromides, and decarboxylative coupling of redox-active esters of alkyl carboxylic acid with high product yields and broad functional group tolerance.
Oxo-rhenium catalyzed reductive coupling and deoxygenation of alcohols
Kasner, Gabrielle R.,Boucher-Jacobs, Camille,Michael McClain,Nicholas, Kenneth M.
supporting information, p. 7257 - 7260 (2016/06/09)
Representative benzylic, allylic and α-keto alcohols are deoxygenated to alkanes and/or reductively coupled to alkane dimers by reaction with PPh3 catalyzed by (PPh3)2ReIO2 (1). The newly discovered catalytic reductive coupling reaction is a rare C-C bond-forming transformation of alcohols.
Manganese- or iron-catalyzed homocoupling of grignard reagents using atmospheric oxygen as an oxidant
Cahiez, Gerard,Moyeux, Alban,Buendia, Julien,Duplais, Christophe
, p. 13788 - 13789 (2008/04/11)
Atmospheric oxygen was used for the first time as an oxidant in metal-catalyzed homocoupling of Grignard reagents. These manganese- or iron-catalyzed reactions are efficient, cheap, and eco-friendly. They are applicable to the large-scale synthesis of symmetrical conjugated compounds. Copyright
Mild TiIII- and Mn/ZrIV-catalytic reductive coupling of allylic halides: Efficient synthesis of symmetric terpenes
Barrero, Alejandro F.,Herrador, M. Mar,Quilez Del Moral, Jose F.,Arteaga, Pilar,Arteaga, Jesus F.,Dieguez, Horacio R.,Sanchez, Elena M.
, p. 2988 - 2995 (2007/10/03)
(Chemical Equation Presented) Two new efficient methods for the regioselective homocoupling of allylic halides using either catalytic Ti III or the combination Mn/ZrIV catalyst have been developed. The regio- and stereoselectivity of the process proved to increase significantly when the Mn/ZrIV catalyst is used as the coupling reagent and when cyclic substituted allylic halides are used as substrates. The use of Lewis acids such as collidine hydrochloride allowed the quantity of catalyst to be lowered up to 0.05 equiv. We have proved the utility of these protocols with the synthesis of different terpenoids such as (+)-β-onoceradiene (1), (+)-β-onocerine (2), squalene (5), and advanced key-intermediates in the syntheses of (+)-cymbodiacetal (3) and dimeric ent-kauranoids as xindongnin M (4a).
Photogeneration and reactivity of 1,n-diphenyl-1,n-azabiradicals
Leo, Edgar A.,Domingo, Luis R.,Miranda, Miguel A.,Tormos, Rosa
, p. 4439 - 4444 (2007/10/03)
The 1,5-diphenyl-1,5-azapentanediyl biradical Ia was generated by photolysis of 1,2-diphenylazacyclopentane (pyrrolidine 1a). Among the reaction pathways followed by Ia, C-N bond reformation with ring closure was found to be the predominating process, as determined by separate irradiation of either of the pure enantiomers of 1a. Disproportionation was a minor process and took place only via H abstraction by the C5 benzylic radical. Another minor pathway was C5-aryl coupling, with formation of 5-phenyl-2,3,4,5-tetrahydro-1H-benzo[b] azepine (4a), which is equivalent to photo-Claisen rearrangement of 1a. Likewise, the 1,4-diphenyl-1,4-azabutanediyl biradical Ib was generated by photolysis of 1,2-diphenylazacyclobutane (azetidine 1b). This species underwent predominating C2-C3 cleavage, as indicated by the extensive styrene formation. Although NI-C4 bond reformation also took place, this is not the major pathway occurring from Ib. Besides, C4-aryl coupling to give 4-phenyl-1,2,3,4- tetrahydroquinoline (4b) was also observed. All the possible reaction pathways were theoretically studied at the UB3LYP/6-31G* computational level; the results were found to be in good agreement with the experimental observations.
Copper catalyzed oxidation of organozinc halides
Su, Xianbin,Fox, David J.,Blackwell, David T.,Tanaka, Kiyotaka,Spring, David R.
, p. 3883 - 3885 (2007/10/03)
A wide range of organozinc substrates may be oxidized in the presence of catalytic copper to give carbon-carbon bonds in high yield. The Royal Society of Chemistry 2006.
Deoxygenative dimerization of benzylic and allylic alcohols, and their ethers and esters using lanthanum metal and chlorotrimethylsilane in the presence of a catalytic amount of iodine and copper(I) iodide
Nishino, Toshiki,Nishiyama, Yutaka,Sonoda, Noboru
, p. 635 - 641 (2007/10/03)
Benzylic and allylic alcohols were deoxygenatively dimerized by a treatment with lanthanum metal and chlorotri-methylsilane in the presence of a catalytic amount of iodine, giving the corresponding coupling products, alkanes, in moderate-to-good yields. This dimerization reaction was dramatically accelerated by the addition of a catalytic amount of copper(I) iodide. Similarly, ethers and esters were deoxygenatively dimerized by La/Me3SiCl/cat.I2/cat.CuI system in the presence of a catalytic amount of H2O.
Trimethyl phosphite as a trap for alkoxy radicals formed from the ring opening of oxiranylcarbinyl radicals. Conversion to alkenes. Mechanistic applications to the study of C-C versus C-O ring cleavage
Ding, Bangwei,Bentrude, Wesley G.
, p. 3248 - 3259 (2007/10/03)
Trimethyl phosphite, (MeO)3P, is introduced as an efficient and selective trap in oxiranylcarbinyl radical (2) systems, formed from haloepoxides 8-13 under thermal AIBN/n-Bu3SnH conditions at about 80 °C. Initially, the transformations of 8-13, in the absence of phosphite, to allyl alcohol 7 and/or vinyl ether 5 were measured quantitatively (Table 1). Structural variations in the intermediate oxiranylcarbinyl (2), allyloxy (3), and vinyloxycarbinyl (4) radicals involve influences of the thermodynamics and kinetics of the C-O (2 → 3, k1) and C-C (2 → 4, k2) radical scission processes and readily account for the changes in the amounts of product vinyl ether (5) and allyl alcohol (7) formed. Added (MeO)3P is inert to vinyloxycarbinyl radical 4 and selectively and rapidly traps allyloxy radical 3, diverting it to trimethyl phosphate and allyl radical 6. Allyl radicals (6) dimerize or are trapped by n-Bu3SnH to give alkenes, formed from haloepoxides 8, 9, and 13 in 69-95% yields. Intermediate vinyloxycarbinyl radicals (4), in the presence or absence of (MeO)3P, are trapped by n-Bu3SnH to give vinyl ethers (5). The concentrations of (MeO)3P and n-Bu3SnH were varied independently, and the amounts of phosphate, vinyl ether (5), and/or alkene from haloepoxides 10, 11, and 13 were carefully monitored. The results reflect readily understood influences of changes in the structures of radicals 2-4, particularly as they influence the C-O (k1) and C-C (k2) cleavages of intermediate oxiranylcarbinyl radical 2 and their reverse (k-1, k-2). Diversion by (MeO)3P of allyloxy radicals (3) from haloepoxides 11 and 12 fulfills a prior prediction that under conditions closer to kinetic control, products of C-O scission, not just those of C-C scission, may result. Thus, for oxiranylcarbinyl radicals from haloepoxides 11, 12, and 13, C-O scission (k1, 2 → 3) competes readily with C-C cleavage (k2, 2 → 4), even though C-C scission is favored thermodynamically.
