Rhodium acetate-catalyzed

The rhodium acetate catalyzed addition of ethyl diazoacetate to MCP (1) gave spiropentane 619 in high yield (Scheme 89) [6e]. The same compound 619 was obtained in lower yield by a Simmons-Smith reaction to methylenecyclo-propane 217 [164],... 

Rhodium acetate catalyzed cyclopropanation of methylenecycloalkanes with diazocarbonyl compounds (equation 9) provides a direct method for preparation of functionalized SPC27. 

Rhodium acetate-catalyzed diazo decomposition has been used in a synthesis of the pyrrole 51, illustrating a route to several similar 3-oxypyrrole systems (Equation 11) <2002SL1913>. Similar annulations of some related fluorine containing substrates resulted in various unusual fluoropyrrole derivatives <20030L745>. 

The rhodiumcarbene intermediate, which is believed to be the active species in rhodium acetate catalyzed cyclopropanations with diazo compounds, shows electrophilic reactivity. Thus, diazopropenes preferentially add to electron-rich alkenes, demonstrated by the reaction of 3-diazo-l,l-dichloropropene (15) with 2-trimethylsiloxybuta-l,3-diene (16) . A mixture of Z-configurated divinylcyclopropanes 17 and rearranged dienones 18 was obtained (see also Section 1. B.2.4.5.1. for further examples of the formation of seven-membered rings such as 18). 

The rhodium acetate-catalyzed decomposition of l-diazo-4-(benzyloxy)butan-2-one and related compounds offers a way to substituted tetrahydrofuranones a Stevens [ 1,2]-shift of a cyclic oxonium ylide is involved in this reaction (Equation (89)) <92J0C3479>. 

In particular, the rhodium acetate catalyzed carbenoid intramolecular insertion reactions has been demonstrated to be an efficient and regiospecific method for the construction of various heterocycles [2,77] such as azetidine, pyrrolidine, piperidine, tetrahydrofuran and... 

Rhodium Acetate Catalyzed Carbene Reactions Another reaction involving a metal carbene is illustrated by Equation 14.91, where Rh2(OAc)4 is the catalyst. A diazoketone acts as a source of a carbene that inserts into an activated C—H bond. The presumed intermediate rhodium carbene complex is too unstable to isolate. 

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