Iron, tricarbonyl synthesis

Germacyclopentadie ne, 1 - exo-fl uoro-1 -methyl-2,3,4,5-tetraphenyl-iron tricarbonyl complex structure, 1, 617 Germacyclopentane, 1-phenyl-bromination, 1, 607 Germacyclopentanes, 1, 605-609 chemical properties, 1, 607-608 synthesis, 1, 605-607 Germacyclopentenes synthesis, 1, 610-612 Germacyclopent-3-enes properties, 1, 612 reactions... 

The double bond transposition could also be achieved by the conversion of an intermediate for PGA2 synthesis into a 1,3-diene iron tricarbonyl complex from which PGC2 was synthesized in four steps. The Fe(CO)3 diene complex which survived the Wittig reaction was cleanly removed by Collins reagent in the subsequent step (Ref. 10). 

The synthesis of the trismethylenemethane iron tricarbonyl complex [(CH2)3C]-Fe(CO)3 was reported by Emerson et al. in 1966 (27). The geometry of this compound in the gas phase was investigated by Almenningen et al. (28) using electron diffraction methods. These authors pointed out some structural peculiarities which were not amenable to a simple explanation, in particular, why the hypothetical planar (CH2)3C radical is distorted when bound to the Fe(CO)3 conical fragment in such a way that the carbon atoms of the CH2 groups are displaced toward — the iron atom (Fig. 9). 

In a series of classic studies, Pettit et al. reported the synthesis of (cyclobutadiene)iron tricarbonyl together with a variety of electrophilic substitution reactions of this aromatic system (Scheme S).25-27... 

Apart from the di- and oligoolefm iron tricarbonyl complexes, which nowadays are frequently used in organic synthesis [71, 72], the chemistry of the readily accessible cyclohepatriene chromium and molybdenum tricarbonyls 2 and 3 was the focus of intense research efforts as well. Only a few months after the synthesis of 2 and 3 was published [58,59], both Hyp Dauben and Peter Pauson reported that these compounds react with triphenylmethyl tetrafluoro-borate in methylene chloride to give the tropylium complexes 4 and 5 in excellent yield (Scheme 7.1) [73, 74]. Later this method of hydride abstraction was also used for the preparation of the tropylium cation itself and subsequently led to the generation of several cationic rc-complexes of iron, manganese and cobalt [71, 72], The reactions of the cations of 4 and 5 with nucleophilic... 

In the penultimate step of a synthesis of the unstable antibiotic Streptazolin, an iron tricarbonyl group co-ordinated to a 1.3-diene unit and two benzyl ethers were severed simultaneously using tribromoborane at -90 °C [Scheme 4.148].274 Tribromoborane has also been used to deprotect a phenolic benzyl ether in the presence of two phenolic methyl ethers in a synthesis of the alkaloid Lythrancepine [Scheme 4.149].275... 

Investigations into the synthesis and reactivity of -diene iron tricarbonyl complexes are among the most active areas of research in iron organometalhc chemistry. A nnmber of excellent reviews are available for the reader seeking greater detail than can be provided here. ... 

The use of cyclic and acyclic diene iron tricarbonyl complexes (see Diene Complexes) in organic synthesis of... 

Cyclobutadiene iron tricarbonyl complexes can be isolated and have been utilized in organic synthesis. Both intra- and intermolecular [2 + 2] cycloadditions of alkenes with cyclobutadiene complexes are observed upon decomplexation using CAN or TMANO (Schemes 164-165). The stereochemistry of the aUcene is retained in the product. Iron tricarbonyl diene complexes are compatible with metathesis reactions... 

Removal of —Fe(CO)z (6, 624). The cation of cycloheptadiene has found limited use in synthesis because of limited stability. However, the iron tricarbonyl... 

Initial attempts to prepare 7r-cycloheptatrienyl-iron tricarbonyl complexes were not successful—the products often being 7r-cycloheptadienyl-iron tricarbonyl derivatives (60). In 1964 Mahler, Jones, and Pettit (162) reported the synthesis of a complex [(C7H7)Fe(CO)3] BF4 by the following route ... 

Lithium alkynylcuprates react with haloallenes to give similar skipped diacetylenes (see below). The related skipped enynes can be prepared by treatment of (pentadienyl)iron(tricarbonyl) halide complexes with dilithium trialkynylcuprates, the compounds being isolated as the iron(tricarbonyl)(diene) complexes (Scheme 4). Further examples of alkylation reactions of copper alkynides are illustrated in Scheme 5. Reaction between a lithium cyanoaikynecuprate and an iodoallene leads to a skipped diacetylene. This useful reaction has been used by Corey in his synthesis of hybridalactone (Scheme 6). °... 

Chiral eyelopropanes. Carrie et al.6-1 have developed a highly enantioselective synthesis of cyclopropanes from the aldehyde 2, in which the butadiene group is protected as the iron tricarbonyl complex. The complex (2) is resolved by the method of Kelly and Van Rheenan (5, 289-290), and the two optical isomers are then converted separately into a cyclopropanealdehyde (5a and 5b) as formulated. A sulfur ylide such as (CH3)2S=CHCOOCH3 can be used in place of diazomethane for cyclopropanation. Optical yields are >90%. 

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