6929-08-4Relevant academic research and scientific papers
Chemo- and Regioselective Functionalization of Polyols through Catalytic C(sp3)-C(sp3) Kumada-Type Coupling of Cyclic Sulfate Esters
Ramírez-Contreras, Rodrigo,Morandi, Bill
, p. 3718 - 3721 (2016/08/16)
This contribution describes a copper-catalyzed, C(sp3)-C(sp3) cross-coupling reaction of cyclic sulfate esters, a distinct class of electrophilic derivatives of polyols, with alkyl Grignard reagents to afford functionalized alcohol products in good yields. The method is operationally simple and highlights the potential of cyclic sulfate esters as highly reactive substrates in catalytic, chemoselective polyol transformations.
A palladium nanoparticle-nanomicelle combination for the stereo-selective semihydrogenation of alkynes in water at room temperature
Slack, Eric D.,Gabriel, Christopher M.,Lipshutz, Bruce H.
, p. 14051 - 14054 (2015/02/19)
The addition of NaBH4 to Pd(OAc) 2 in water containing nanomicelles leads to the generation of H2 and Pd nanoparticles. Subsequent reduction of disubstituted alkynes affords Z-alkenes in high yields. These reactions are general, take place in water at ambient temperatures, and offer recycling of the aqueous reaction mixture along with low overall E Factors.
Copper-catalyzed enantioselective allylic substitution with alkylboranes
Shido, Yoshinori,Yoshida, Mika,Tanabe, Masahito,Ohmiya, Hirohisa,Sawamura, Masaya
supporting information, p. 18573 - 18576 (2013/01/15)
The first catalytic enantioselective allylic substitution reaction with alkylboron compounds has been achieved. The reaction between alkyl-9-BBN reagents and primary allylic chlorides proceeded with excellent γ-selectivities and high enantioselectivities under catalysis of a Cu(I)-DTBM-SEGPHOS system. The protocol produces terminal alkenes with an allylic stereogenic center branched with functionalized sp3-alkyl groups. The reaction with a γ-silicon-substituted allyl chloride affords an efficient strategy for the enantioselective synthesis of functionalized α-stereogenic chiral allylsilanes.
Tin-free giese reaction and the related radical carbonylation using Alkyl iodides and cyanoborohydrides
Ryu, Ilhyong,Uehara, Shohei,Hirao, Hidefumi,Fukuyama, Takahide
body text, p. 1005 - 1008 (2009/04/07)
Tin-free Giese reaction and the related radical carbonylation process proceeded efficiently in the presence of sodium cyanoborohydride and tetrabutylammonium cyanoborohydride. The reaction took place chemoselectively at the carbon-iodine bond but not at the carbon-bromine and carbon-chlorine bonds. The iodine atom transfer followed by hydride reduction of the resulting carbon-iodine bond is proposed as a possible mechanism.
Fragmentation of carbonyl oxides by N-oxides: An improved approach to alkene ozonolysis
Schwartz, Chris,Raible, Joseph,Mott, Kyle,Dussault, Patrick H.
, p. 3199 - 3201 (2007/10/03)
Ozonolysis of alkenes in the presence of amine N-oxides results in the direct formation of aldehydes. This reaction, which appears to involve an unprecedented trapping and fragmentation of the short-lived carbonyl oxide intermediates, avoids the hazards associated with generation and isolation of ozonides or other peroxide products.
New polymer anchored chiral amino oxazolines as effective catalysts for enantioselective addition of diethylzinc to aldehydes
Shaikh, Nadim S,Deshpande, Vishnu H,Bedekar, Ashutosh V
, p. 5587 - 5589 (2007/10/03)
The application of a new type of polymer anchored chiral amino-oxazolinyl ligand as catalyst for the enantioselective addition of diethylzinc to aldehydes is reported. The catalyst is effective at a low ligand concentration and can be reused with minimal loss of activity.
Alkyliron and Alkylcobalt Reagents, IX. - Rearrangement of Aliphatic Terminal Epoxides to Methyl Ketones by Iron Alkyl Reagents instead of Co2(CO)8 or Noble Metal Catalysts
Kauffmann, Thomas,Neiteler, Christel,Neiteler, Gabriele
, p. 659 - 666 (2007/10/02)
The highly selective rearrangement of aliphatic terminal epoxides to methyl ketones, hitherto possible only with Co2(CO)8 or noble metal catalysts, occurs smoothly with Me4FeLi2, Me3FeLi, or the catalytic systems (R = Me, Bu).This was demonstrated by the rearrangement of 1-decene oxide (1) to 2-decanone (2) (yield 80-81percent; Table 1) and 6-bromo-1-hexene oxide (5) to 6-bromo-2-hexanone (6) (yield 78percent, Me4FeLi2 applied only).The competition reaction of Me4FeLi2 with 1 and 2-octanone (8) (mole ratio 0.5:1:1) led to 87percent 2-methyl-2-octanol (9) and not to the rearrangement 1 --> 2.This indicates that Me4FeLi2 - in contrast to the opposite behavior of organo cuprates - reacts faster with ketones than with the aliphatic terminal epoxides.By treatment of 1 with methyl derivatives of Mn(II), Co(II), and Ni(II) or with Bu4FeLi2 (Table 2) other products (3, 4) besides 2 were formed.The rearrangement of 1 with Me4FeLi2 is assumed to start with an oxidative addition and yields 2 as its Li or Fe enolate (trapped with acetanhydride to give 64percent of 20) after reductive elimination of CH4.The catalytic rearrangement of 1 with very probably occurs in an analogous manner with an super-ate complex Me4FeLi2(MeLi)n as the active species and the Li enolate of 2 as end product (Scheme 4).The aromatic terminal epoxides styrene oxide and α-methylstyrene oxide give various products in the reaction with Me4FeLi2 or Me3FeLi, including the deoxygenation products styrene and α-methylstyrene.These products are exclusively formed on treatment of the epoxides with Me4MnLi2. (Prepared, hitherto in the literature not described compounds: 7 and 10-15.) - Key Words: Organoiron compounds / Iron catalysts / Ketone synthesis
Selective reduction of less reactive carbonyl groups in the presence of diborane and sodium bisulfite on silica gel
Chihara, Teiji,Wakabayasi, Tamie,Taya, Kazuo,Ogawa, Haruo
, p. 720 - 724 (2007/10/02)
The less reactive carbonyl group of a mixture of reducible groups of carbonyl compounds was preferentially reduced with diborane on silica gel by first forming the adduct of the more reactive carbonyl group with sodium bisulfite.For example, 4-acetylbenzaldehyde could be converted to 4-(1-hydroxylethyl)benzaldehyde in 93percent selectivity; in a mixture of 4-phenyl-acetophenone and 4-phenylbenzaldehyde, biphenylethanol was preferentially formed in 95percent yield with 16percent yield of 4-phenylbenzyl alcohol.Silica gel and sodium bisulfite were essential for this selective reaction.Aliphatic and aromatic aldehydes and unhindered cyclohexanones could be selectively protected by this method.
SELECTIVE PROTECTION OF CARBONYL COMPOUNDS BY GIRARD'S REAGENT USING SILICA GEL AS A SOLID SUPPORT
Chihara, Teiji,Waniguchi, Erika,Wakabayashi, Tamie,Taya, Kazuo
, p. 1647 - 1648 (2007/10/02)
The Girard's reagent, which gives water-soluble derivatives of carbonyl compounds, was used together with silica gel as a protective reagent of them in a non-aqueous solvent system.Less hindered or more reactive carbonyl compounds were selectively protected by this method in competitive reductions.
