Thioketenes complexes

This route is similar to those syntheses starting from mononuclear complexes with a terminal vinylidene ligand (see Scheme 17).54,55 In both cases a thioketene complex is formed as an intermediate, which is then reduced. 

In a closely related reaction the thioketene complex 106210 was reduced by sequential addition of H and H+ to give the thioketone complex 107. However, compared to the reaction of 104 the sequence of H+ and H addition is inverse. Complex 107 is coordinatively unsaturated and therefore added PPh3 rapidly (Scheme 25).109... 

Methylation of r/ -coordinated thioketene complexes of the type [CoCp(PMe3X>/ -SC=CR2)] [453, R2 = CMe2(CH2)3CMe2, Bu 2] gives sulfonium ions (269), but a proton attacks the double bond to give thioacyl complexes (454) (270). Certain thio- and selenoaldehyde complexes of... 

A mixture of the sulphur heterocycles (147) and (148) reacts with the iridium complexes [LaIr(CO)Cl] (L = PhjP or PhaPMe) to yield the bis(tri-fluoromethyl)thioketene complexes (149) and (150), and the l,l-bis(trifluoro-methyI)ethene-2,2-dithiolato-complex (151). ... 

A mixture of 3,6-bis-(2,2,2-trifluoro-l-trifluoromethylethylidene)-s-tetra-thian (147) and 3,5-bis-(2,2,2-trifluoro-l-trifluoromethylethylidene)-l,2,4-trithiolan (148) reacts with h8p)4Pt to yield the l,l-bis(trifluoromethyl)-ethene-2,2-dithiolate complex (181) and the bis(trifluoromethyl)thioketen complex (182). The complex (PhaPMe)4Pt yields only a dithiolate complex. ... 

Reaction with Thioketones. The reaction of thiobenzophenone derivatives (48) and similar compounds with Fe2(CO)9 has been studied by Alper. It has been shown to result in the formation of orf/jo-metalated complexes (49) in reasonable to high yields (eq 30). Treatment of the complexes (49) with Mercury(II) Acetate effects orf/io-mercuration. Thioketene complexes have also been examined. Complexes of type (49) offer a new route to lactones. ... 

The versatility and selectivity of the Lawesson reagent is also evidenced in the synthesis of the highly complex alkaloid 19-hydroxytubotaiwine287, in which a ketolactam is transformed into a thionethiolactam (equation 41). Also, Diels-Alder cycloadducts can be thionated with 52 and, upon thermolysis at high temperatures (FVT), afford the corresponding thioketenes which are trapped in situ2m (equation 42). 

Only one isolated example of formation of thioketene and thioaldehyde dimolybdenum complexes has been reported507, but in contrast, zirconocene thioacetaldehyde and thiobenzaldehyde complexes, introduced by Buchwald, have been the subject of several studies508, including their application in the synthesis of novel antimony thiametallacy-cles 148509 (equation 156). Compound 146 was generated in situ and, after reaction with alkynes, gave rise to metallacycles 147 which, by treatment with SbCR, afforded 148. 

We have reported the first electroactivity of a thioketene dimer compound [116]. The CV measurement of 2,4-dibenzylidene-l,3-dithietane (31), which was prepared by a basic dimerization of phenylthioketene derived from ben-zyltriphenylphosphonium chloride, showed irreversible two-step oxidation peaks at 0.25 and 0.61 V vs Ag/Ag+, indicating that 31 acts as a stronger electron donor than 2,6-bisphenyl-l,4-dithiafulvene (30) and TTF (2). The dimer (31) can form a 1 1 CT complex with TCNQ in DMSO. Cycloaddition polymerization of bisthioketene derived from p-xylenebis(triphenylphosphoni-um chloride) gave a -conjugated polymer (32) with thioketene dimer unit in the main chain (Scheme 12). This polymer was the first polymer contain-... 

Acetyl groups in desaurins may be oxidized to carboxylic acid groups by sodium hypochlorite without affecting the basic bis(methylene)dithietane structure. Treatment of 575 with bromine in chloroform effects replacement of the two methine hydrogen atoms by bromine atoms.An unusual methylene-1,3-dithietane reacts with bis(trifluoromethyl)thioketene to give a complex structure embodying a new methylene-l,3-dithietane and a 2-methylenethietane. Bis-... 

The distribution of electron density in the sulfur-containing ligands is modified to allow the thiones to function as two unsymmetrically opposed 4e donors in the complex of type 4. The compound has no metal-metal bond. Behrens and co-workers 30) as well as Seyferth et al. 15) prepared symmetrical complexes in which the ligands are bound similarly to the one drawn below the two iron atoms in 4. In the Behrens compounds, prepared from thioketenes, the a-thio carbon atom is sp hybridized in contrast to the sp hybridization which occurs when the two iron atoms are held together by the O-thioformate groups in Seyferth s compound. The latter group proposed two completely different, competing pathways for the formation of complexes of types 1 and 3. 

Photochemical desulfurization of thiocarbonates occurs with [Fe(CO)j] to give mononuclear as well as trinuclear (type 8) carbene complexes (24). A similar reaction affords desulfurization of diphenylcyclopropenethione (22). The thioketene cluster 13 reacts quantitatively, but in a more complicated way, with a thioketene to form a dinuclear vinylidene complex (14). 

Addition of phenylethynethiolate or -selenate to the carbene complex 185 (M = Cr or W, R = Me or Et, E = S or Se) affords an anionic adduct (186) which, unexpectedly, contains a reactive thioketene function. Electrophiles can attack either at the sulfur or at the carbon a thereto to produce coordinated carbenes or thio- and seleno aldehydes and esters [H4J45). 

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 thioketene dimetallic complex 493 reacts with H to give an anionic thioacyl complex (494). Protonation of494, by cleavage of a metal - carbon bond, gives a thioaldehyde complex (495) which is stabilized by PPhj... 

As mentioned in various sections, nucleophilic addition of phenylethyn-ethiolate or phenylethyneselenolate, PhC=CE (E = S or Se), to the car-bene complex [W(CO)s C(OEt)Ph)] affords thioketene adducts (186), which, depending on the electrophile used, function as electrophilic synth-ons for either coordinated thio- or selenoacyl anions, [W(CO)5E=CR] , or their structural isomers, anionic thio- or selenocarbene complexes. 

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