2833-34-3Relevant academic research and scientific papers
Remote Arylative Substitution of Alkenes Possessing an Acetoxy Group via β-Acetoxy Elimination
Kakiuchi, Fumitoshi,Kochi, Takuya,Kumagai, Takaaki,Muto, Kazuma
supporting information, p. 24500 - 24504 (2021/10/19)
Palladium-catalyzed remote arylative substitution was achieved for the reaction of arylboronic acids with alkenes possessing a distant acetoxy group to provide arylation products having an alkene moiety at the remote position. The use of β-acetoxy elimination as a key step in the catalytic cycle allowed for regioselective formation of unstabilized alkenes after chain walking. This reaction was applicable to various arylboronic acids as well as alkene substrates.
A chemoenzymatic synthesis of ceramide trafficking inhibitor HPA-12
Kanojia, Seema V.,Chatterjee, Sucheta,Chattopadhyay, Subrata,Goswami, Dibakar
, p. 490 - 496 (2019/03/07)
A chemoenzymatic synthesis of the title compound has been developed using an efficient and highly enantioselective lipase-catalyzed acylation in a hydrophobic ionic liquid, [bmim][PF6], followed by a diastereoselective asymmetric dihydroxylatio
Highly Focused Library-Based Engineering of Candida antarctica Lipase B with (S)-Selectivity Towards sec-Alcohols
Cen, Yixin,Li, Danyang,Xu, Jian,Wu, Qiongsi,Wu, Qi,Lin, Xianfu
supporting information, p. 126 - 134 (2018/12/05)
Candida antarctica lipase B (CALB) is one of the most extensively used biocatalysts in both academia and industry and exhibits remarkable (R)-enantioselectivity for various chiral sec-alcohols. Considering the significance of tailor-made stereoselectivity in organic synthesis, a discovery of enantiocomplementary lipase mutants with high (R)- and (S)-selectivity is valuable and highly desired. Herein, we report a highly efficient directed evolution strategy, using only 4 representative amino acids, namely, alanine (A), leucine (L), lysine (K), tryptophan (W) at each mutated site to create an extremely small library of CALB variants requiring notably less screening. The obtained best mutant with three mutations W104V/A281L/A282K displayed highly reversed (S)-selectivity towards a series of sec-alcohol with E values up to 115 (conv. 50%, ee 94%). Compared with the previously reported (S)-selective CALB variant, W104A, a single mutation provided less selectivity, while the synergistic effects of three mutations in the best variant endow better (S)-selectivity and a broader substrate scope than the W104A variant. Structural analysis and molecular dynamics simulation unveiled the source of reversed enantioselectivity. (Figure presented.).
Tert-Butyl Nitrite: Organic Redox Cocatalyst for Aerobic Aldehyde-Selective Wacker-Tsuji Oxidation
Ning, Xiao-Shan,Wang, Mei-Mei,Yao, Chuan-Zhi,Chen, Xian-Min,Kang, Yan-Biao
supporting information, p. 2700 - 2703 (2016/06/15)
An aldehyde-selective aerobic Wacker-Tsuji oxidation is developed. Using tert-butyl nitrite as a simple organic redox cocatalyst instead of copper or silver salts, a variety of aldehydes were achieved as major products in up to 30/1 regioselectivity as well as good to high yields at room temperature.
Dynamic kinetic resolution of homoallylic alcohols: Application to the synthesis of enantiomerically pure 5,6-dihydropyran-2-ones and δ-lactones
Warner, Madeleine C.,Shevchenko, Grigory A.,Jouda, Suzan,Bogar, Krisztian,Baeckvall, Jan-E.
, p. 13859 - 13864 (2013/10/22)
Dynamic kinetic resolution of various homoallylic alcohols with the use of Candida antarctica lipase B and ruthenium catalyst 2 afforded homoallylic acetates in high yields and with high enantioselectivity. These enantiopure acetates were further transfor
Direct synthesis of B-allyl and B-allenyldiisopinocampheylborane reagents using allyl or propargyl halides and indium metal under Barbier-type conditions
Hirayama, Lacie C.,Haddad, Terra D.,Oliver, Allen G.,Singaram, Bakthan
, p. 4342 - 4353 (2012/06/30)
We report the first one-pot process for the asymmetric addition of allyl, methallyl, and propargyl groups to aldehydes and ketones using B-chlorodiisopinocampheylborane (dDIP-Cl) and indium metal. Under Barbier-type conditions, indium metal was
Study on the coupling of acyclic esters with alkenes - The synthesis of 2-(2-hydroxyalkyl)cyclopropanols via cascade cyclization using allylsamarium bromide
Tu, Yawei,Zhou, Liejin,Yin, Ruifeng,Lv, Xin,Flowers Ii, Robert A.,Choquette, Kimberly A.,Liu, Huili,Niu, Qingsheng,Wang, Xiaoxia
supporting information, p. 11026 - 11028 (2013/01/15)
The radical cyclization between aliphatic acyclic esters and alkenes was achieved unprecedentedly in the presence of allylsamarium bromide with HMPA and H2O as additives. The cascade radical cyclization-ring-opening- anionic cyclization allowed facile and efficient access to 2-(2-hydroxyalkyl) cyclopropanols from readily available materials.
Rhodium-catalyzed allylation of benzyl acetates with allylsilanes
Onodera, Gen,Yamamoto, Eriko,Tonegawa, Shota,Iezumi, Makoto,Takeuchi, Ryo
experimental part, p. 2013 - 2021 (2011/10/09)
Benzyl acetate reacted with allyltrimethylsilane to give an allylation product in the presence of a catalytic amount of the (cyclooctadiene)rhodium(I) chloride dimer {[Rh(cod)Cl]2}, sodium tetrakis[3,5- bis(trifluoromethyl)phenyl]borate (NaBARF), and triphenyl phosphite [P(OPh) 3] in refluxing 1,2-dichloroethane. Primary, secondary and tertiary benzyl acetates could be used for the reaction. Moreover, allylation of gem-benzyl acetate was possible with [Rh(cod)Cl]2, NaBARF, and P(OPh)3. Monoallylation and diallylation of gem-benzyl acetate could be controlled by altering the reaction conditions. Cationic rhodium species generated in situ act as a Lewis acid catalyst to give a benzyl carbocation by elimination of the acetoxy group from the benzylic carbon. Copyright
Silicomolybdic acid supported on silica gel: An efficient catalyst for Hosomi-Sakurai reactions
Murugan, Kaliyappan,Srimurugan, Sankareswaran,Chen, Chinpiao
experimental part, p. 5621 - 5629 (2011/08/09)
Silicomolybdic acid that is supported on silica gel (50 wt %) efficiently catalyzes the high-yielding Hosomi-Sakurai allylation of carbonyl compounds by allyltrimethylsilane in the presence of benzyl alcohol. The reaction rates of inactive substrates and the yields were greatly increased when preformed acetals were used as substrates.
Synthesis and thermal decomposition of N,N-dialkoxyamides
Digianantonio, Katherine M.,Glover, Stephen A.,Johns, Jennifer P.,Rosser, Adam A.
scheme or table, p. 4116 - 4126 (2011/06/28)
N,N-Dialkoxyamides 1c, a virtually unstudied member of the new class of anomeric amides, amides bearing two electronegative atoms at nitrogen, have been synthesised in useful yields directly from hydroxamic esters using phenyliodine(iii)bis(trifluoroacetate) (PIFA). Infrared carbonyl stretch frequencies and carbonyl 13C NMR properties have been reported, which support strong inhibition of amide resonance in these amides. Their thermal decomposition reactions in mesitylene at 155°C proceed by homolysis to form alkoxyamidyl and alkoxyl free radicals in preference to HERON rearrangements to esters. The reactions follow first-order kinetics and for a series of N,N-dimethoxy-4-substituted benzamides, activation energies of 125-135 kJ mol-1 have been determined together with weakly negative entropies of activation.
