Trimethylsilyl cyanide , catalyst

Pd(0) complex, or with KCN and a Ni(0) catalyst. Halides can be converted to the corresponding nitriles by treatment with trimethylsilyl cyanide in the presence of catalytic amounts of SnCl4 R3CCI + Me3SiCN —> R3CCN. ... 

Two groups simultaneously found that trimethylsilyl cyanide reacts with disubstituted acetylenes in the presence of a Pd catalyst to form silylated 2-amino-5-cyanopyrroles 194 or 195 [133, 134], These reactions are run neat and a variety of Pd species are successful in this transformation [133]. In the case of unsymmetrical diaryl acetylenes, the reaction is not regioselective [134],... 

Cyanation of aldehydes and ketones is an important chemical process for C C bond formation." " Trimethylsilyl cyanide and/or HCN are commonly used as cyanide sources. The intrinsic toxicity and instability of these reagents are problematic in their applications. Acetyl cyanide and cyanoformates were used as cyanide sources in the enantioselective cyanation of aldehydes catalyzed by a chiral Ti complex and Lewis base (Scheme 5.31)." The Lewis base was necessary for the good yields and selectivities of these reactions. The desired products were obtained in the presence of 10mol% triethyl amine and 5mol% chiral titanium catalyst (Figure 5.14). Various aliphatic and aromatic aldehydes could be used in these reactions. 

The most frequently used method for the preparation of isoquinoline Reissert compounds is treatment of an isoquinoline with acyl chloride and potassium cyanide in water or in a dichloromethane-water solvent system. Though this method could be successfully applied in a great number of syntheses, it has also some disadvantages. First, the starting isoquinoline and the Reissert compound formed in the reaction are usually insoluble in water. Second, in the case of reactive acyl halides the hydrolysis of this reaction partner may became dominant. Third, the hydroxide ion present could compete with the cyanide ion as a nucleophile to produce a pseudobase instead of Reissert compound. To decrease the pseudobase formation phase-transfer catalysts have been used successfully in the case of the dichloromethane-water solvent system, resulting in considerably increased yields of the Reissert compound. To avoid the hydrolysis of reactive acid halides in some cases nonaqueous media have been applied, e.g., acetonitrile, acetone, dioxane, benzene, while utilizing hydrogen cyanide or trimethylsilyl cyanide as reactants instead of potassium cyanide. 

The Reissert reaction of 3,4-dihydro-p-carboline (213) has also been studied 47,48). It has been shown that 3,4-dihydro-p-carboline (213) afforded 1-cyano-2,9-dibenzoyl-l,2,3,4-tetrahydro-P-carboline (214) with a phase-transfer catalyst and trimethylsilyl cyanide (Scheme 27). However, the normal Reissert product 2-benzoyl-l-cyano-l,2,3,4-tetrahydro-p-carboline (215) was obtained when a catalytic amount of anhydrous aluminum chloride was used in addition to the trimethylsilyl cyanide reagent. Reaction of 214 with sodium... 

The cyanide ion is an ambident nucleophile and isocyanides may be side products. If the preparation of isocyanides is desired, they can be made the main products by the use of silver or copper(I) cyanide1577 (p. 368). Vinylic bromides can be converted to vinylic cyanides with CuCN,1578 with KCN, a crown ether, and a Pd(0) complex,1579 with KCN and a Ni(0) catalyst,15 1 or with K4Ni2(CN)6.1581 Tertiary halides can be converted to the corresponding nitriles by treatment with trimethylsilyl cyanide in the presence of catalytic amounts of SnCl4 RjCCl + Me3SiCN — R3CCN.1582... 

A binaphthol-modified Ti(IV) complex effects enantioselective addition of trimethylsilyl cyanide to aldehydes to form optically active cyanohydrin derivatives (Scheme 124). The highest ee value of 82% is achieved in the reaction of isovaleraldehyde with 20 mol % of the catalyst (286a). Use of a tartrate-derived modifier in combination with molecular sieves 4A is also effective for this type of addition and results in... 

New ligands for a polymetallic Gd catalyst used in the ring opening of meso-aziridines with trimethylsilyl cyanide and 2,6-dimethylphenol have been developed.44... 

Cyanosilylation of methyl ketones has been carried out using diphenylmethylphos-phine oxide and trimethylsilyl cyanide, generating a phosphorus isonitrile-type species, Ph2MeP(OTMS)(N=C ), as the reactive intermediate.271 A chiral oxazaborolidinium ion catalyst renders the reaction enantioselective. 

Shibasaki and co-workers disclosed a general asymmetric Strecker-type reaction that was controlled by bifunctional Lewis acid-Lewis base catalyst 14 [10], N-Fluorenylimines 15 underwent catalytic asymmetric Strecker-type reactions with binaphthol catalyst 14 to give a-aminonitriles 16 in good to excellent enantioselectivities and yields (Scheme 6). a-Aminonitrile 16 (R = Ph) could then be converted to a-aminoamide 17 in several steps. Aromatic, aliphatic, heterocyclic and a,/f-unsaturated imines 15 were used as general substrates in these reactions. The origin of the highly enantioselective cataylsis by 14 is believed to be attributed to the simultaneous activation of imines and trimethylsilyl cyanide by the... 

Two other types of catalysts have been investigated for the enantioselective Strecker-type reactions. Chiral N-oxide catalyst 24 has been utilized in the trimethylsilyl cyanide promoted addition to aldimines to afford the corresponding aminonitriles with enantioselectivities up to 73% ee [14]. Electron-deficient aldimines were the best substrates, but unfortunately an equimolar amount of catalyst 24 was used in these reactions. The asymmetric Strecker addition of trimethylsilyl cyanide to a ketimine with titanium-based BINOL catalyst 25 gave fast conversions to quarternary aminonitriles with enantiomeric excesses to 59%... 

Pyridinecarbaldehyde reacts with trimethylsilyl cyanide in the presence of the catalysts derived from either enantiomer of 3,3 -bis(diethylaminomethyl)-substituted binaphthol or 1,1 -bi-2-naphthol (BINOL) and... 

A flame-dried 5-mL flask was charged with catalyst (19.2 mg, 50 pmol, 5 mol%), 2-bromo-2-cyclohexen-l-one (109 pL, 1 mmol, 1 equiv), trimethylsilyl cyanide (TMSCN 0.294 mL, 2.2 mmol, 2.2 equiv) and CH2CI2 (2.0 mL). The flask was sealed with a rubber septum and Parafilm , and the reaction cooled to —78 °C and stirred for 15 min. 2,2,2-Trifluoroethanol (73 pL, 1 mmol, 1.0 equiv) was then added via syringe and the reaction stirred at —78 °C for 12 h, after which the contents of the flask were placed under high vacuum at —78 °C for 5 min to remove excess HCN (CAUTION HCN is highly toxic). After warming to r.t., the entire reaction mixture was loaded onto a silica gel column for FC. Elution (hexanes ethyl acetate, 20 1) gave the expected product as a white solid (261 mg, 95% yield, 97% ee). 

Trimethylsilyl)benzophenone cyanohydrin has been prepared previously by the addition of trimethylsilyl cyanide to benzophenone using an aluminum chloride catalyst.4 The preparation of cyanohydrin silyl ethers described in the synthesis is based on... 

The LiC104 (3 mol %)-CH2Cl2 medium also proved to be a catalyst for the addition of trimethylsilyl cyanide (Me3SiCN) to aldehyde 79. Unfortunately, the diastereoselectivity was low (syn anti = 57 43) this might be attributed to the reversibility of the reaction (Sch. 59) [108]. 

Reetz et al. found that chiral 1-boracyclopentyl chloride or methoxide can be used as a catalyst in the reaction of 3-methylbutanal and trimethylsilyl cyanide (Eq. 72) [42]. Although the asymmetric induction and yield are not good, this is the first example of chiral induction by an organoborane in the hydrocyanation of aldehydes. 

The only known metal catalyst for the asymmetric catalytic Strecker reaction is the aluminum salen catalyst 465 (Sch. 65) recently reported by Sigman and Jacobsen [97]. They prepared 11 different chiral salen complexes from different transition and main group metals and screened these complexes for the addition of trimethylsilyl cyanide to imine 460 at room temperature. The aluminum catalyst 465 was optimum in terms both of asymmetric induction and rate. This constitutes the first aluminum salen complex successfully developed for an asymmetric catalytic reaction. 

Kobayashi et al. also reported interesting chemoselectivity of aldehydes and imines in the Yb(OTf)3-catalyzed addition reactions of silyl enol ether, allylstannane or trimethylsilyl cyanide [12]. In the competitive reactions between aldehydes and imines, the imines reacted faster than the aldehydes (Tables 4-6). This tendency is not unique to Yb as catalyst selectivity is similar for other Ln(OTf)3. Nuclear magnetic resonance (NMR) studies revealed selective formation of an imine-Yb(OTf)3 complex in the presence of an aldehyde. This preference was reversed when conventional Lewis acids (SnCE, TiCU, TMSOTf, and BF3 OEt2) were used. 

Trimethylsilyl cyanide reacts with diphenylcyclopropenone in the presence of Fe2(CO)9 or PPh3 as catalyst to give the aminofuran derivative 73 (40-60%) (Eq. (10)). Other phosphines and transition metal phosphine complexes are effective catalysts. A similar reaction was achieved using cycloheptenocyclopropenone. Desilylprotonation of compound 73 was achieved in hot MeOH containing a trace of p-TsOH, but the primary amine was trapped in situ as a cycloadduct without isolation (87JOC4408). 

---