Tertiary isocyanide

Isocyanides can be reduced to the corresponding hydrocarbon by (TMS SiH. The reaction can be considered as the deamination of primary amines since isocyanides are obtained via formylation of amines and dehydration. The efficiency of the reduction is independent of the nature of the alkyl substituent. That is, primary, secondary and tertiary isocyanides at 80 °C gave the corresponding hydrocarbon in good yields21. An example is given in equation 184. 

In the laboratory of T.-L. Ho, the total synthesis of the novel marine sesquiterpene (+)-isocyanoallopupukeanane was completed." In the endgame of the synthesis, it was necessary to install the isocyano group onto the tricyclic trisubstituted alkene substrate so that it will occupy the more substituted carbon atom (according to Markovnikov s rule). The Ritter reaction was chosen to form the required carbon-nitrogen bond. The alkene substrate was dissolved in glacial acetic acid and first excess sodium cyanide followed by concentrated sulfuric acid was added at 0 °C. The reaction mixture was stirred at ambient temperature for one day and then was subjected to aqueous work-up. The product A/-alkyl formamide was subsequently dehydrated with tosyl chloride in pyridine to give rise to the desired tertiary isocyanide which indeed was identical with the natural product. 

Reductive deamination can be performed in reasonable yields via phenylimidoyl chlorides prepared from benzoyl derivatives of primary amines. Imidoyl chloride derivatives decompose on heating with TBTH and AIBN in xylene to yield alkanes (equation 80) . Primary amines can also be reductively deaminated in high yields via isocyanide derivatives. Formylation-dehydration transforms an amino group into an isocyanide quite routinely. Reductive removal of isocyanide can be performed with sodium naphthalenide in hydrocarbon solvents " or with TBTH in the presence of AIBN ". The TBTH reduction works equally well for primary, secondary and tertiary isocyanides and yields are good (equation 81) ". ... 

CHsSNa in an aprotic solvent or by BusSnH. Both reactions have free-radical mechanisms.Tertiary nitro compounds can be reduced to RH by NaHTe. The compound Bu3SnH also reduces isocyanides (RNC, prepared from RNH2 by formylation followed by 17-33) to a reaction that can also be... 

Isocyanides can be prepared by elimination of water from N-alkylformamides with phosgene and a tertiary amine. Other reagents, among them TsCl in quino-... 

When the reaction is over, add- concentrated hydrochloric acid to decompose the isocyanide and pour it away after the odour is no longer discernible. The test is extremely dehcate and will often detect traces of primary amines in secondary and tertiary amines it must therefore be used with due regard to this and other factors. 

Complexes of the type (L)AuR have been isolated with a large variety of donors L, including predominantly tertiary phosphines and isocyanides. The dinuclear complex (dppm)(AuMe)2 has been prepared by treatment of (dppm)(AuCl)2 with MeLi and structurally characterized.17 Examples (L)AuR with a carbene ligand L are also known. A simple methyl compound was prepared from the chloride complex with dimethylmagnesium (Equation (l)).18... 

Rhenium(0) compounds are rare and frequently lie in the realm of the organometallic chemistry. A simple example is decacarbonyldirhenium(0) in which two staggered, square-pyramidal Re(CO)5 fragments are held together by a single rhenium-rhenium bond. Substitution of carbonyl ligands is possible by tertiary phosphines and arsines, silanes and isocyanides, and binuclear Re-Re, Mn-Re, and Co-Re complexes have been studied. " Successive replacement of CO ligands can readily be observed by vibrational spectroscopy. This has been demonstrated... 

TRI- AND TETRANUCLEAR CARBONYL-RUTHENIUM CLUSTER COMPLEXES CONTAINING ISOCYANIDE, TERTIARY PHOSPHINE, AND PHOSPHITE LIGANDS. RADICAL ION-INITIATED SUBSTITUTION OF METAL CLUSTER CARBONYL COMPLEXES UNDER MILD CONDITIONS... 

The tertiary phosphines PMe2Ph, CH2(PPh2)2, and C2(PPh2)2, the phosphite P(OC6H4Me-p)3, and the isocyanide CN-t-Bu are available from Strem or Pressure Chemicals. 

Caution. Due to evolution of highly toxic carbon monoxide (a colorless and odorless gas), and also because of the toxic nature and bad odor of tertiary phosphine, phosphite, or isocyanide ligands, these reactions should be performed in a well-ventilated hood. 

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... 

Amino-3-cyanofurans (307) are obtained by base catalyzed condensation of the acyloins (306) with malonodinitrile, and on acid hydrolysis yield the butenolides (308) (Scheme 80) (66CB1002). Diketene and an isocyanide react to give the lactone (309) in the presence of a tertiary base (73GEP2222405). When diphenylketene is treated with bis(cycloocta-l,5-diene)nickel and pyridine, the complex Ni(py)2(Ph2C=CO)2 is formed which is converted into compound (310) by carbon monoxide (78JOM(l52)C29). 

Low oxidation states are generally stabilized by ligands which have both a donor (lone pairs) and n acceptor (either empty d orbitals or empty antibonding Jt orbitals) capability. Examples of common ligands with these characteristics are carbon monoxide, cyanide ion, alkyl and aryl isocyanides, tertiary phosphines and arsines, and alkyl or aryl phosphites. 

When simple nickel(II) salts are treated with thiols, in most cases stable thiolate-bridged polymers are formed. In a number of cases, treating these polymers with either tertiary phosphines or isocyanides gave mononuclear mixed-ligand complexes (equation 204).1951 These mononuclear complexes, due to the presence of terminal thiolates which possess lone pairs, can further react with nickel(II) and give trinuclear complexes (equation 205).1952... 

Platinum(IV) isocyanide complexes PtCU(CNR)2 and [PtCl2(CNR)2(PMe2Ph)2]2+ have been prepared by the addition of Cl2 to the corresponding platinum(II) compounds (equation 118).363 It is probable that the trans influence of the isocyanide ligand on platinum(IV) is greater than that of a tertiary phosphine. 

The solid-supported reagent, 2, was subsequently used to convert isothiocyanates to isonitriles (Scheme 5.7). Primary, secondary and tertiary alkyl isocyanides, as well as aromatic analogues were synthesised using this microwave assisted methodology. Isocyamide products were produced in excellent yields and high purity in 30 min to 2 h at 140°C. 

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