Epoxidation phenyldiazomethane

CpFe(CO)2(thf)]+, is generated by protonation of the respective iron-methyl complex with HBF4 in THF solution. Iron-catalyzed reactions of phenyldiazomethane with aldehydes resulted in mixtures of ketones and epoxides [29]. 

CpFe(CO)2(THF)](BF4) gives ds-epoxides as minor product and ketones as major product with phenyldiazomethane (Sch. 30) [140], Evidence presented suggests that a Fe-Lewis acid-catalyzed process is operative rather than a metal carbene mechanism. The use of ethyldiazoacetate in this reaction gives, besides the expected j8-ketoester (minor product), the 3-hydroxy-2-phenylacrylic acid ethyl ester [141],... 

The addition of a diazocarbonyl compound to an alkene with metal catalysis is an effective method for the formation of cyclopropanes, as discussed above. However, direct addition to aldehydes, ketones or imines is normally poor. Epoxide or aziridine formation can be promoted by trapping the carbene with a sulfide to give an intermediate sulfur ylide, which then adds to the aldehyde or imine. For example, addition of tetrahydrothiophene to the rhodium carbenoid generated from phenyldiazomethane gave the ylide 131, which adds to benzaldehyde to give the trans epoxide 132 in high yield (4.104). On formation of the epoxide, the sulfide is released and hence the sulfide (and the rhodium complex) can be used in substoichiometric amounts. 

The iron cationic complex [Cp(CO)2Fe(THF)]BF4 catalyzed epoxidation reaction of benzaldehyde with phenyldiazomethane [88]. a-Benzaldehyde iron complex as... 

Pereira A, Martin C, Maya C, Belderrain TR, Perez PJ. An effective dual copper- and sulfide-catalytic system for the epoxidation of aldehydes with phenyldiazomethane. Adv Synth Catal. 2013 355 2942-2951. 

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