CH341 Ch 9-10 terminologies

vicinal dihalide

compound that contains two halogen atoms attached to adjacent carbon atoms

germinal dihalide

presence of two halogen atoms attached to the same carbon atom in a molecule

acetylide anion

negatively charged carbon species formed from terminal alkynes

enol

hydroxyl group bonded to carbon atom that is part of carbon-carbon double bond (C=C(OH))

lindlar’s catalyst

heterogeneous catalyst made of palladium on calcium carbonate, used for selective hydrogenation of alkynes to cis-alkenes

retrosynthesis

target molecule is deconstructed into simpler precursor structures; allows for sequence of reactions needed to synthesize it to be identified

tautomers

constitutional isomers that differ in locations of a hydrogen atom and one or more double bonds, allowing them to interconvert rapidly

tautomerization

chemical reaction that involves interconversion of tautomers; relocation of a hydrogen atom within compound which results in different structural forms of the same molecule

syn addition

addition of two substituents to the same face of a double bond, resulting in specific stereochemistry in product

anti addition

two substituents are added to opposite sides of double or triple bond, resulting in change in stereochemistry

partial hydrogenation of alkynes

alkyne selectively reduced to alkene rather than fully reduced to alkane

multi-step synthesis

involves series of chemical reactions to construct complex molecules from simpler precursors

alkyl halides/haloalkanes

formed when one or more hydrogen atoms in alkane are replaced by halogen atoms

radical initiation step

free radicals are generated from a stable, non-radical precursor; requires energy to overcome energy barrier of homolytic cleavage of weak bonds to give free radicals

radical propagation step

reaction of free radical with substrate or another free radical to form new radical; allows reaction to continue and produce more products

radical termination step

stops propagation of free radicals and brings reaction to close by involving the reaction of two free radicals to form a more stable product

allylic position

carbon atom adjacent to double bond in alkene

vinylic position

carbon atoms directly involved in carbon-carbon double bond

NBS

reagent used for bromination reactions, including allylic bromination and formation ofbromohydrins

carbanion

anion in which carbon has unshared pair of electrons and carries negative charge, typically with three substituents and eight total valence electrons

peroxide

R-O-O-R’, derived from hydrogen peroxide (H2O2) by replacing one or both hydrogen atoms with organic groups 

organometallic compounds

contain at least one bond between metallic element and carbon atom from organic molecule

grignard reagent

organomagnesium compounds that serve as powerful nucleophiles in organic synthesis, enabling formation of new carbon-carbon bonds

gillman’s reagent

organometallic compound used in organic synthesis for forming carbon-carbon bonds

coupling reaction

involve formation of new carbon-carbon bonds, often facilitated by metal catalysts

oxidation in organic compounds

increase in carbon-heteroatom bonds and decrease in carbon-hydrogen bonds, leading to higher oxidation state

reduction in organic compounds

decrease in number of carbon-heteroatom bonds and increase in number of carbon-hydrogen bonds

oxidative addition

metal complex reacts with substrate, resulting in increase of oxidation state of metal and formation of new bonds

transmetallation

transfer of ligands from one metal to another, allowing for formation of new carbon-carbon bonds by enabling coupling of organic halides with nucleophiles

reductive elimination

reduction of oxidation state of metal center, leading to formation of new covalent bonds between ligands; essential for formation of C-C and C-X bonds