Reaction pathway of methylenation of carbonyl compounds with bis(iodozincio)methane.

About 40 years have passed since methylene dizinc reagent was discovered as a substitute for Wittig reagent. Density functional theory (DFT) calculations have been performed to understand the reaction pathways of methylenation of carbonyl compounds with bis(iodozincio)methane. The present computational/theoretical study concluded that the methylenation reaction with gem-dizinc reagent proceeds as a two-step reaction, that is, methylene addition (RDS) and olefination.

Transition-metal-catalyzed sequential cross-coupling of bis(iodozincio)methane and -ethane with two different organic halides.

Bis(iodozincio)methane, prepared from diiodomethane and zinc, reacts with an organic halide in the presence of a transition-metal catalyst to give an iodozinciomethylenated compound; this then reacts with another organic halide to form a C--C bond. The overall process connects two electrophiles with one carbon atom. Bis(iodozincio)ethane can also undergo this transformation, yielding a new stereogenic center.