Midterm 2 - Alkynes + Dienes

what does CH3CH2O- do

adds bonds by displacing hydrogens and leaving groups

can go from an alkane to an alkyne

what does -NH2 do

deprotonates terminal alkynes to make alkyne anions

can then be used to add carbon chains and create internal alkyne

how to make a terminal alkyne anion from an alkane

two CH3CH2O- and then one -NH2

how do Br carbon chains react with alkynes

the Br is used on an alkyne anion to add carbon chains

what does H2/Pd do (heterogeneous)

hydrogenates alkyne all the way, fully saturated

2 reactions take from alkyne to an alkane

what does H2/Pd do (Lindlar’s catalyst)

partially hydrogenates

only from alkyne to alkene

is the addition of a lindlars catalyst cis or trans

cis (z configuration)

what does Na, NH3 (l) do

Na reduces double bond and NH3 donates hydrogens

2 reactions take from alkyne to alkene

4 reactions take from alkyne to alkane

is the reaction with Na, NH3 (l) cis or trans

this makes a trans alkene

what is the selectivity for the first HX reaction

anti with markovnikov rule

what is the selectivity for the second HX reaction

also markovnikov yielding a geminal dihalide

what is a geminal dihaline

where both the halogens are on the same carbon

is the selectivity for HX reactions different on terminal vs internal alkynes

for terminal alkynes its always geminal, markovnikov

for internal its a mixture

what additional step does an Hg, H2O reaction require

tautomerization

what is tautomerization

the movement of an alkene bond to onto an alcohol to form =O

what does a Hg, H2O reaction do

adds an enol onto the more substituted carbon, and then tautomerizes the compound, yields a ketone

what is the selectivity on an Hg, H2O reaction

markovnikov selectivity

Which solvent do X2 reactions occur in and why

CCl4 because its a non interacting solvent

what is the stereospecificity for the first X2 reaction

anti addition

what extra step does X2, H2O require

tautomerization

what is the selectivity on the X2, H2O reaction

markovnikov with an anti addition, OH goes on the more substituted carbon

what configuration does X2, H2O yield

a trans configuration

which two reactions have anti markovnikov selectivity

Cy2, BH, H2O2, H2O, NaOH

HBr, ROOR, heat

what does Cy2, BH, H2O2, H2O, NaOH yield

creates an aldehyde on a terminal alkyne, ketone on an internal alkyne

what kind of base should be used in a Cy2, BH, H2O2, H2O, NaOH reaction with an internal alkyne

an even bulkier base such as tert butyl oxide O-C(CH3)3

which reaction has a mix of syn and anti addition

HBr, ROOR, heat