Dithioester complexes

Ir(CO)(CS2)(PPh3)2](BPli4). It was formulated as an octahedral species with a rc-bonded CS2 ligand, as in (64). However, when attempts were made to alkylate [Ir(CO)(CS2)(PPh3)2]+ to form the dithioester complex, which should have reacted with acids in an alternative route to the thiocarbonyl complex, the reactions proved unsuccessful. The complex turned out to be... 

These compounds are nucleophihc at the noncoordinated sulfur, and undergo alkylation there with iodomethane or benzyl bromide to give initially (128) (which may be isolated as the PFe salt) and ultimately (129) (equation 28). They also react with electron-deficient alkynes, possibly by a dipolar mechanism, to afford cyclized iron carbene complex (130). Finally, compounds (129) are subject to attack by some nucleophiles hydride attack occurs initially at the metal, but ultimately gives ) -dithioester complexes, such as (131). ... 

The anionic adducts 186 abstract from the disulfide or diselenide, R E E R which adds to the a carbon of the thioketene function, to form the unsaturated dithioester complexes of type 228 84). 

The dithioester complexes of type 418, in which the ligand coordinates as an allylic type, 4e donor, are converted by alkylation to the stabilized, 2e donor dithiocarbenium complexes (419) (256). Addition of CS2, fol-... 

Dithioesters bearing a chiral auxiliary have been used in asymmetric thia-Diels-Alder reactions with acyclic 1,3-dienes to produce cycloadducts with a diastereomeric excess of 90%. A Cu(II)bis(oxazoline)/dithioesters complex has been proposed to rationalize the chiral induction ... 

Extensive studies of enzyme-substrate complexes by resonance Raman spectroscopy (RR) have prompted the synthesis of new peptide bond modifications such as thionoesters and dithioesters (Scheme l7)t82-83l within simple model substrates. The resulting acyl-enzyme complexes are especially amenable to RR analysis with cysteine proteases such as papain due to formation of the transient dithioester intermediates. 

Peptide dithioesters have been used as model compounds to study the conformations of dithioacyl enzyme complexes. 1 3 Dithioesters are also used as thioacylating agents that introduce the thioamide bonds into the peptide backbone in order to study the structures of endothiopeptidesJ4,5 ... 

Another method starts with the above-postulated intermediate oxoalkyl dithioesters (224). These dithioesters (224) can be cyclized to the corresponding 1,3-dithiolylium salts (31) in the presence of strong acids by warming either in 70% perchloric acid or concentrated sulfuric acid. The results are sometimes improved by the presence of H2S or of the complex H2S/BF3 (80AHC(27)151). 

Complexes of dmit2- are commonly generated either via ligand transfer from [Zn(dmit)2]2- (see Section III.G) or by salt metathesis using Na2dmit. Alkali metal salts of dmit2- are prepared by hydrolysis of the thioester dmit[C(0)Ph)]2. This dithioester is prepared by treatment of [Zn(dmit)2]2- with PhC(Q)Cl and... 

The main drawback in the use of thiocarbonyl compounds as spin traps was represented by the fact that in most cases the resulting spin adducts either were as transient as the attacking radicals (aliphatic thioketones and dithioesters) or were characterized by very complex ESR spectra (thiobenzophenone and its derivatives). It was only after the introduction of thiobenzoyltriphenylsilane la that the use of thiocarbonyl compounds in spin trapping experiments acquired some practical value. 

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