3618-18-6Relevant articles and documents
Mechanism-based design and optimization of a catalytic electrophilic cyclopropanation without diazomethane
Tchawou, Augustin A. S. W.,Raducan, Mihai,Chen, Peter
supporting information, p. 180 - 191 (2017/11/27)
Iodomethylboron compounds, either the trifluoroborate or a boronic ester, cyclopropanate electron-rich olefins and unprotected allylic alcohols with Pd catalysts according to a novel, designed catalytic cycle. Proposed intermediates in a "diverted Heck" mechanism are observed by means of spectroscopic studies and by isolation and X-ray crystallographic characterization, which together with reaction kinetics point to a separation of rate-determining and product-determining steps, and a mechanism-based optimization of the yield, selectivity, and scope of the catalytic electrophilic cyclopropanation. The reaction with crystalline, air-stable, nonhygroscopic, and nontoxic reagents provides an alternative to Simmons-Smith-type reactions, as well as cyclopropanation procedures that require the use of diazomethane.
A palladium-catalyzed methylenation of olefins using halomethylboronate reagents
Hartog, Tim Den,Toro, Juan Manuel Sarria,Chen, Peter
supporting information, p. 1100 - 1103 (2014/03/21)
Methylenation of electron-rich olefins is a highly challenging reaction, for which we have developed a new methodology exploiting Pd-catalysis and halomethylboronate reagents, the latter replacing diazomethane and zinc carbenoids as methylene donors. Optimization of the reaction for norbornene and extension to several other olefins are reported, with reasonable-to-excellent yields of cyclopropanes in combination with β-H elimination products. Several mechanisms are plausible for this methylenation reaction.
