Aluminum phthalocyanine: an active and simple catalyst for cyanosilylation of aldehydes

Aluminum phthalocyanine (AlPc) in the presence of Ph₃PO acts as a highly effective catalyst for cyanosilylation of various aldehydes to the corresponding cyanohydrin trimethylsilyl ethers. The reaction proceeds smoothly with 5 mol% catalyst loading at room temperature, giving up to 96% yield. Copyright © 2007 John Wiley & Sons, Ltd.     

TBD-catalyzed cyanosilylation of aldehydes and ketones

This study examines the catalytic efficacy of 1,5,7-triazabicyclo[4,4,0]dec-5-ene (TBD) in the cyanosilylation of aldehydes and ketones. In an aldehyde reaction, the corresponding products were obtained at high yield using minimal TBD (0.01?mol%). TBD was similarly effective in various ketone reactions.     

Catalytic cyanosilylation of ketones with simple phosphonium salt

In the presence of 1-5 mol % of benzyltriphenylphosphonium chloride, a wide variety of unconjugated and conjugated, acyclic and cyclic ketones were transformed to their corresponding cyanohydrin silyl ethers in excellent yields.     

Polystyrene-supported TBD as an efficient and reusable organocatalyst for cyanosilylation of aldehydes, ketones, and imines

Polystyrene-supported TBD (PS-TBD) catalyzes cyanosilylation of both aldehydes and ketones using TMSCN to give the corresponding products in high yields. Imines were also converted into the desired α-cyanoanimes under the same conditions. PS-TBD was easily recovered and reused without significant loss of catalytic activity.     

Catalytic cyanosilylation of ketones using organic catalyst 1,1,3,3-tetramethylguanidine

1,1,3,3-Tetramethylguanidine acts as a highly effective catalyst for cyanosilylation of various ketones and aldehydes to the corresponding cyanohydrin trimethylsilyl ethers in up to 99% yield. The reaction proceeds smoothly with 0.1 mol % catalyst loading at 25 °C under solvent-free conditions.     

Copper perchlorate hexahydrate: a highly efficient catalyst for the cyanosilylation of aldehydes

Cu(ClO₄)₂·6H₂O has been found to be an efficient catalyst for cyanosilylation reaction of aldehydes in THF at room temperature with low catalytic loading (1.0 mol%) in short reaction time (mostly within 10 min). Copyright © 2008 John Wiley & Sons, Ltd.     

Iron phthalocyanine as new efficient catalyst for catalytic transfer hydrogenation of simple aldehydes and ketones

Catalytic transfer hydrogenation (CTH) of various aldehydes and ketones was studied using iron phthalocyanine catalyst, in order to substitute the typically used rare transition metals (Ir, Rh, Ru) with an easily available and less expensive metal. Iron phthalocyanine was found to be an efficient hydrogenation catalyst and its immobilized version was successfully prepared. The immobilized iron phthalocyanine was also active in the CTH reaction of various carbonyl compounds, and it was easy to handle and possible to recycle. Copyright © 2014 John Wiley & Sons, Ltd.     

氮氧双功能salen催化剂在酮的不对称硅氰化反应中的应用

通过在催化剂的不同位置同时引入LALB（Lewis acid/Lewis base）双功能基团（包括氮氧偶极基团和金属钛中心）来改善其催化活性和立体控制能力,合成基于salen骨架结构的新型氮氧双功能催化剂.在相对温和的条件下成功的将该类双功能催化剂应用于酮的不对称硅氰化反应,表现出了中等程度的选择性和非常高的反应活性...     

Ultramicromethods: VI. Lithium aluminum hydride reduction of aldehydes and ketones

The lithium aluminum hydride reduction of 1 ng of the aldehyde, decanal and of the ketone, 2-decanone is described. The method should be applicable to further classes of compounds amenable to reduction by complex hydrides.     

Thiourea-catalyzed enantioselective cyanosilylation of ketones

The new chiral amino thiourea catalyst 3d promotes the highly enantioselective cyanosilylation of a wide variety of ketones. The hindered tertiary amine substituent plays a crucial role with regard to both stereoinduction and reactivity, suggesting a cooperative mechanism involving electrophile activation by thiourea and nucleophile activation by the amine.     

Layered double hydroxides (LDHs): As efficient heterogeneous catalyst for the cyanosilylation of aromatic aldehydes

We report the first application of Layered Double Hydroxides (LDHs) as efficient and novel heterogeneous catalyst for the cyanosilylation of aldehydes with excellent yields and simple work up. The reaction between different aldehydes with electron-withdrawing and releasing groups and trimethylsilyl cyanide (TMSCN) proceeds in dry CH₂Cl₂ at room temperature in the presence of Mg-Al-Cu LDH. The catalyst recycled and reused for four times without loss of catalytic activity. The structures of all compounds were corroborated spectroscopically (¹H- and ¹³C-NMR, and elemental analysis). A plausible mechanism for this type of reaction is proposed.     

Highly active bifunctional salenTi(IV) catalysts for asymmetric cyanosilylation of aldehydes and TMSCN

A novel enantiopure salen ligand bearing a diphenylphosphine oxide on the 3-position of one aromatic ring was synthesized and combined with Ti(Oi-Pr)₄ as a monometallic bifunctional catalyst for asymmetric cyanosilylation reaction of aldehydes with trimethylsilyl cyanide (TMSCN). The catalyst system exhibited excellent activity and moderate enantioselectivity. The addition of TMSCN to 4-nitrobenzaldehyde in the presence of 1 mol% catalyst loading could complete within 10 min at ambient temperature. An intramolecularly cooperative catalysis was observed in this system wherein the central metal Ti(IV) is suggested to play a role of Lewis acid to activate aldehydes while the appended diphenylphosphine oxide worked as Lewis base to activate TMSCN.     

A mild and efficient cyanosilylation of ketones catalyzed by a Lewis acid-Lewis base bifunctional catalyst

A new family of bifunctional catalysts (N-oxides-Ti(OⁱPr)₄ (2:1)) containing a Lewis acid and a Lewis base was developed and applied to the catalytic cyanosilylation of ketones. Utilizing rac((1R,2S) and (1S,2R))-1-(2′-pyridylmethyl)-2-diphenylhydroxymethylpyrrolidine N-oxide-titanium (2:1) complex and N-benzyl-diethanolamine N-oxide-titanium (2:1) complex as catalysts, the cyanosilylation products were obtained in 42-97% yield. Based on experimental phenomena and kinetic studies, a catalytic cycle was proposed to explain the remarkable activities of these catalysts. Investigations indicated that rac((1R,2S) and (1S,2R))-1-(2′-pyridylmethyl)-2-diphenylhydroxymethylpyrrolidine N-oxide-titanium (2:1) complex and N-benzyl-diethanolamine N-oxide-titanium (2:1) complex should promote the reaction via a dual activation of the ketone by the titanium and TMSCN by the N-oxide.     

Cations of aldehydes and ketones: an ESR study

Exposure of dilute solutions of acetaldehyde, acetone and cyclohexanone in fluorotrichloromethane to ⁶⁰Co γ-rays at 77 K gave the corresponding radical cations, characterised by ESR spectroscopy.     

MoO2Cl2] as catalyst for hydrosilylation of aldehydes and ketones

The high valent molybdenum-dioxo complex [MoO2Cl2] catalyzes the addition of dimethylphenylsilane to aldehydes and ketones to afford the corresponding dimethylphenylsilyl ethers in quantitative yield.     

Synthetic talc as a solid base catalyst for condensation of aldehydes and ketones

Magnesium organo silicates (MOSs; synthetic talc) as such and with amine surface functionalities were synthesized by sol–gel method under non-hydrothermal conditions and characterized by spectroscopic techniques. The synthesized talc samples were observed to be thermally stable up to 200 °C in nitrogen atmosphere and used as catalysts for condensation of aldehydes and ketones. Application of synthetic talc as a solid base catalyst for condensation of aldehydes and ketones is being reported for the first time. The effect of solvent, solvent to reactant molar ratio, amount of catalyst and temperature was studied in detail for self-condensation of propanal. High conversion (86%) of propanal with 95% selectivity of 2-methylpentenal was achieved using dimethyl sulphoxide as a solvent. The kinetic study was carried out for the condensation of propanal catalyzed by amine functionalized MOS under optimum reaction conditions. Catalyst was re-used without significant loss in activity up to three cycles.     

Lithium hydroxide: A simple and an efficient catalyst for Knoevenagel condensation under solvent-free Grindstone method

Synthesis of arylmethylidenes from araldehydes and active methylene compounds catalyzed by catalytic amount of lithium hydroxide (LiOH·H₂O) in the absence of a solvent under Grindstone method is reported. The reactions go to completion within 1–5 min and give products in excellent yields at 26 °C.     

Solid-supported Pd(0): an efficient heterogeneous catalyst for aerobic oxidation of benzyl alcohols into aldehydes and ketones

Solid-supported nano- and microparticles of Pd(0) (SS-Pd) were used as heterogeneous catalysts for aerobic oxidation of benzyl alcohols. Primary and secondary benzyl alcohols gave the corresponding products in good yields. In addition, the catalysts could be reused up to five runs without significant loss of activities.     

Nickel(II) chloride as an efficient and useful catalyst for chemoselective thioacetalization of aldehydes

A wide variety of acyclic and cyclic dithioacetals can be prepared chemoselectively from the corresponding aldehydes by employing a catalytic amount of nickel(II) chloride in dry CH₂Cl₂-MeOH (5:1) at room temperature in good yields. Some of the major advantages of this procedure are high chemoselectivity, ease of operation, high yields and also compatibility with other protecting groups.