Cyclic boronates are formed in cross-metathesis reactions of allylic alcohols and allylboron reagents. Treatment with hydrogen peroxide and sodium hydroxide yields stereodefined allylic diols (Eq. 15).
Diana grew up in Sofia, Bulgaria and got her Masters degree at Sofia University. After she earned her Ph.D. in organic chemistry from the University of Zurich in Switzerland she moved to the States for a post doc and never left. She ran her first metathesis reaction in Paul Hanson’s group at the University of Kansas, the reaction worked really well and everybody else in the group started doing metathesis. Diana joined Materia in the fall of 2002.
Metathesis Method in Organic Synthesis.
Jean Baptiste Bourg
Jean-Baptiste (J-B) was born in Ambilly, France and grew up in the French Alps, where he especially enjoyed skiing. He studied chemistry in Paris, earning an engineering degree from Chimie ParisTech, and did research on ruthenium-catalyzed hydrogenation. The weather in Paris being a little too rainy, he decided to move to Riverside, California. He spent the next four years trying to isolate diradicals and carbenes, and eventually completed his Ph.D. Willing to apply his knowledge on carbene chemistry to olefin metathesis, J-B worked with Prof. Grubbs before joining Materia in fall 2008.
PDF Download alkene metathesis in organic synthesis Books For ..
Olefin metathesis involves the exchange of two alkylidene groups to generate two new olefins from one or more starting alkenes. Cleavage of the carbon-carbon double bond is accompanied by the formation of two new carbon-carbon double bonds. This reaction was first observed in 1931, investigated by Du Pont and other manufacturers in the 1950's, and finally defined by Calderon in 1967. Partly due to its relevance to petrochemical industry, olefin metathesis reactions have been investigated extensively. Four general classes of reactions have emerged: cross metathesis, an intermolecular reaction of two alkenes; ring-opening metathesis polymerization (ROMP), in which a cyclic alkene opens to form a polyolefin; ring-opening metathesis (ROM), the opening of a cyclic alkene to form a diene; and ring-closing metathesis (RCM), in which reaction of a diene affords a cyclic alkene and a small olefinic byproduct. RCM is the focus of this article (Eq. 1).
Synthesis of Symmetrical Trisubstituted Olefins by Cross Metathesis
Andy grew up in the suburbs of Philadelphia and attended Temple University as an undergraduate. In college he studied chemistry and spent his free time playing rhythm guitar in a band. One day, he skipped band practice to attend a graduate student literature seminar entitled, “Ruthenium-Catalyzed Olefin Metathesis.” Despite the teasing he received from his band mates that day, he still spends much of his time thinking about this very topic. After earning his Ph.D in 2005 from Yale University in the field of natural product synthesis, Andy worked as a medicinal chemist for 3 years before joining Materia in the summer of 2008.
RCM has been employed extensively in organic synthesis to ..
The generally accepted mechanism for olefin metathesis involves a series of [2+2] cycloadditions and cycloreversions involving the reactant alkenes and catalytic metal carbenes (Eq. 3). In RCM reactions, cycloaddition of one alkene with the catalyst affords metallacyclobutane intermediate 7 containing a pendant olefin. In a cycloreversion step, a small olefin is expelled and new metal carbene intermediate 8 forms, which still contains a tethered alkene. Intramolecular cycloaddition yields new metallacyclobutane 9, which undergoes cycloreversion to expel the metal carbene catalyst and generate the product cyclic alkene.