4203-49-0Relevant academic research and scientific papers
1,3-O- TO -C-ALKYL MIGRATION OF 1-ALKENYL ALKYL ACETALS AND KETALS CATALYZED BY BORON TRIFLUORIDE. SELECTIVE CROSS- AND REGIOSELECTIVE ALDOL TYPE REACTIONS
Takahashi, Mitsuru,Suzuki, Hiroharu,Moro-Oka, Yoshihiko,Ikawa, Tsuneo
, p. 1079 - 1082 (1982)
1,3-Alkyl migration of 1-alkenyl alkyl acetals and ketals is effectively catalyzed by trifluoroborane etherate to give cross aldol type products selectively.Remarkable regioselectivity is observed in the synthesis of α-alkyl-β-alkoxy-ketones.
Iron-catalyzed protodehalogenation of alkyl and aryl halides using hydrosilanes
Pilli, Ramadevi,Balakrishnan, Venkadesh,Chandrasekaran, Revathi,Rasappan, Ramesh
, p. 1749 - 1753 (2019/02/20)
A simple and efficient iron-catalyzed protodehalogenation of alkyl and aryl halides using phenylhydrosilane is disclosed. The reaction utilizes FeCl3 without the requirement of ligands. Unactivated alkyl and aryl halides were successfully reduced in good yields; sterically hindered tertiary halides were also reduced including the less reactive chlorides. The scalability of this methodology was demonstrated by a gram-scale synthesis with a catalyst loading as low as 0.5 mol%. Notably, disproportionation of phenylsilane leads to diphenylsilane that further reduces the halides. Preliminary mechanistic studies revealed a non-radical pathway and the source of hydrogen is PhSiH3via deuterium labeling studies. Our methodology represents simplicity and provides a good alternative to typical tin, aluminum and boron hydride reagents.
Selective Semi-Hydrogenation of Terminal Alkynes Promoted by Bimetallic Cu-Pd Nanoparticles
Buxaderas, Eduardo,Volpe, María Alicia,Radivoy, Gabriel
, p. 1466 - 1472 (2019/03/07)
The selective semi-hydrogenation of terminal alkynes was efficiently performed, under mild reaction conditions (H 2 balloon, 110 °C), promoted by a bimetallic nanocatalyst composed of copper and palladium nanoparticles (5:1 weight ratio) supported on mesostructured silica (MCM-48). The Cu-PdNPS@MCM-48 catalyst, which demonstrated to be highly chemoselective towards the alkyne functionality, is readily prepared from commercial materials and can be recovered and reused after thermal treatment followed by reduction under H 2 atmosphere.
BiCl3: A versatile catalyst for the tetrahydropyranylation and depyranylation of 1°,2°,3°, allylic, benzylic alcohols, and symmetric diols
Vijaya Durga,Balamurali Krishna,Baby Ramana,Santha Kumari,Vijay,Hari Babu
, p. 1030 - 1034 (2017/05/26)
Bismuth trichloride as mild reagent, has been found to be a worthful catalyst for tetrahydropyranylation of 1°,2°,3°, allylic, benzylic alcohols, and symmetric di-ols. At room temperature the reagent THP(3,4-dihydro-2H-pyran) was successfully employed as pyranylating agent in presence of BiCl3catalyst without the use of a solvent and the yields of the products were found to be 90-96%. Further, the depyranylation of alcohols was achieved in quantitative yield by simple addition of MeOH using the same catalyst. The developed method was showed good chemo-selectivity in symmetrical diols for mono THP protection.
Iron(II) catalyzed reductive radical cyclization reactions of bromoacetals in the presence of NaBH4: optimization studies and mechanistic insights
Kyne, Sara H.,Lévêque, Christophe,Zheng, Shiwen,Fensterbank, Louis,Jutand, Anny,Ollivier, Cyril
, p. 7727 - 7737 (2016/11/18)
5-Exo-trig radical reductive cyclization reactions of bromoacetals are catalyzed by iron in the presence of the reducing agent NaBH4. Both iron(II) and iron(III) were found to effectively mediate these reactions. As shown by cyclic voltammetry, iron(III) can be reduced to an iron(II) precatalyst before passing through an identical reaction mechanism in which monoelectronic activation of the substrate would occur by an anionic hydridoiron(I) complex. Further studies have established that both the substrate (iodo- vs bromo-derivative) and the precatalytic mixture are decisive in determining the reaction outcome.
Room-Temperature Gold-Catalysed Arylation of Heteroarenes: Complementarity to Palladium Catalysis
Cresswell, Alexander J.,Lloyd-Jones, Guy C.
supporting information, p. 12641 - 12645 (2016/08/30)
Tailoring of the pre-catalyst, the oxidant and the arylsilane enables the first room-temperature, gold-catalysed, innate C?H arylation of heteroarenes. Regioselectivity is consistently high and, in some cases, distinct from that reported with palladium ca
Tetrahydropyranylation of alcohols in the presence of a slightly basic, heterogeneous titanium catalyst
Magyar, ágnes,Nagy, Balázs,Hell, Zoltán
, p. 1876 - 1879 (2019/11/28)
4 ? molecular sieve modified with titanium (IV) is an efficient heterogeneous catalyst for the tetrahydropyranylation of alcohols under mild, slightly basic reaction conditions. The catalyst can be reused with good yield after a simple treatment with dichloromethane.
cis-Semihydrogenation of alkynes with amine borane complexes catalyzed by gold nanoparticles under mild conditions
Vasilikogiannaki, Eleni,Titilas, Ioannis,Vassilikogiannakis, Georgios,Stratakis, Manolis
supporting information, p. 2384 - 2387 (2015/02/05)
Supported gold nanoparticles catalyze the semihydrogenation of alkynes to alkenes with ammonia borane or amine borane complexes in excellent yields and under mild conditions. Internal alkynes provide cis-alkenes, making this protocol an attractive alternative of the classical Lindlar's hydrogenation.
Selective transfer semihydrogenation of alkynes with nanoporous gold catalysts
Wagh, Yogesh S.,Asao, Naoki
, p. 847 - 851 (2015/03/03)
A facile, highly chemo- and stereoselective transfer semihydrogenation of alkynes to Z-olefins has been achieved by use of unsupported nanoporous gold (AuNPore) as a heterogeneous catalyst together with formic acid as a hydrogen donor. A variety of terminal/internal and aromatic/aliphatic alkynes were reduced to the corresponding alkenes in high chemical yields with good functional-group tolerance. The catalyst is robust enough to be reused without leaching.
3,5-Dinitrobenzoic acid catalyzed synthesis of 2,3-unsaturated O- and S-glycosides and tetrahydropyranylation of alcohols and phenols
Bodipati, Naganjaneyulu,Palla, Srinivasa Rao,Komera, Venkateshwarlu,Peddinti, Rama Krishna
supporting information, p. 6878 - 6881 (2015/02/02)
A simple procedure for the synthesis of 2,3-unsaturated glycosides in acetonitrile and tetrahydropyranylation of alcohols and phenols in dichloromethane in the presence of 3,5-dinitrobenzoic acid is described. A variety of alcohols and thiols are reacted with glycals to give the desired products in high yields with high α-selectivity.
