Exam 3 other info Flashcards
E in german
entgegen, opposite
Z in german
zusammen, same
heat of hydrogenation
heat released during hydrogenation
allows us to ID stability
higher the heat of hydrogenation, the lower the alkene’s stability
why are more substituted alkenes more stable?
inductive effects and hyperconjugation
cycloalkenes with 5 C or fewer only…
exist in cis form
trans cyclo____ can be isolated and exists as enantiomers
octene
for trans cyclo—- and higher C number, cis is just as stable as trans
decene
Bredt’s rule
bicyclic compounds cannot have double bond at bridgehead unless one ring has 8 C or more
(if they do, they’re unstable)
Zaitsev’s rule
if more than one elimination product (alkene) is possible, the most substituted alkene is the major product
if you have to start an E2 rxn with a 1° halide…
use a bulky base
config. required for E2 to occur
anticoplanar
catalytic cracking
long chain alkane broken into a smaller alkane and an alkene
alkene is purified
dehydrogenation
removal of H2 from alkane to give alkene
requires a lot of energy
regioselectivity yields…
2+ constitutional isomers, with one being the major product
THF
tetrahydrofuran
2 types of halogenation
in anhydrous conditions - yields doubly halogenated product
in aqueous conditions - yields halohydrin (OH and X)
hydrogenation requires…
heat, pressure
catalysts used in hydrogenation
Pt, Pd, Ni
heterogeneous catalysis
substrates in different phases
insoluble catalyst
fine particles of catalyst react with substrate to form products
homogenous catalysis
catalyst is soluble
4 types of information you can get from NMR
- # of signals – types of nuclei
- chemical shift – chemical environment
- area under signal – number of nuclei contributing
- splitting pattern – number of neighbors
unit used to designate chemical shift
𝛅
TMS
tetramethylsilane
reference compound
moves signal downfield
deshielding
multiplicity =
n + 1
used to determine split peak height
Pascal triangle
only — % of C is 13C
1.1%
