Carbenes and carbenoid intermediates

Dediazoniation Reactions Involving Carbene and Carbenoid Intermediates... 

The seemingly limited number of available methods to access cyclopropanes by standard transformations in the laboratory are a result of the inherent ring strain of these systems. The fact that carbenes are intrinsically high-energy species renders them unique in the construction of numerous natural and nonnatural products that include cyclopropanes (Sections 15.2-15.5). However, there have been recent developments in methods that provide access to cyclopropanes via alternative intermediates and mechanistic pathways that are strikingly efficient (Section 15.6). Additionally, carbene and carbenoid intermediates have been reported to partake in a variety of stereoselective C-H insertions (Sections 15.7-15.8). 

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