DuPont Simmons-Smith reaction

The reaction is known as the Simmons-Smith reaction, after the two chemists at the DuPont chemical factory who discovered it in 1958. Even after several decades, it is the most important way of making cyclopropane compounds, though nowadays a variant that uses more easily handled starting materials is often used. Diethyl zinc replaces the Zn/Cu couple of the traditional Simmons-Smitji reaction. In this example, a double cyclopropanation on a C2 symmetric diene derived from tartaric acid gives very good stereoselectivity for reasons we will soon discuss. 

Two DuPont chemists discovered a reagent that converts alkenes to cyclopropanes in better yields than diazomethane, with fewer side reactions. The Simmons-Smith reaction, named in their honor, is one of the best ways of making cyclopropanes. 

Nonhalogenated cyclopropanes can be prepared by the reaction of an aikene with diiodomethane, CH2I2, in the presence of a copper-activated zinc reagent called zinc-copper couple [Zn(Cu)]. This process, the Simmons-Smith reaction, is named for H. E. Simmons and R. D. Smith, DuPont chemists who discovered the reaction in 1959. 

Two chemists at Dupont found that ICH2ZnI is better than diazomethane at converting a C=C bond to a cylcopropane ring. Propose a mechanism for the reaction, now known as the Simmons-Smith reaction in their honor. 

The best method for preparing nonhalogenated cyclopropanes is by a process called the Simmons-Smith reaction. First investigated at the DuPont company, this reaction does not involve a free carbene. Rather, it... 

The year 1958 represents a pivotal moment for the cyclopropanation reaction of olefins. At that time, Simmons and Smith at DuPont reported the reaction of diiodomethane and Zn/Cu couple in the presence of olefins to afford cyclopropanes [56]. An important further advance in the Simmons-Smith cyclopropanation reaction resulted from Dauben s observation that cyclo-hex-2-enol underwent syn-selective methenylation [57, 58]. Additionally, the reaction was noted to be accelerated by the resident allylic hydroxyl group in the substrate. As a representative example, treatment of 87 with CH2I2 and Zn/Cu furnished 88 as a single diastereomer moreover, the parent hydrocarbon (4,4,10-trimethyl-A -octalin) failed to react under similar condi-... 

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