fox organic

why is this the major product

so the major, ph is a large substituent methyl is meduium and H is small. the Me-Li attacks at an angle greater than 90 degree, thru the H, so more favoured. this called Felkin control

justify this

polar model, where Cl is 90 degrees to carbonly

whats happening here

chelation model

so whats difference between the chelation model and carbonyl model

Rule for chelation,

polar group must have lone pairs, but not halogen

2)metal of nucleophile needs to be m2+ or m3+ to be a good lewis acid. but can be lithium if reaction a is not an aldol reaction or b) polar group is O or N, not S

why is anti more major

BF3 group disacitated dipole carbon to oxygen but also dipole on C-O single bond, the dipoles oppose on left hand side which is more stable bc theyre opposite direction, right hand are parallel so reinforce eachother, Nu attacks from bottom near H hence why major

might be a little difficult but whats the newman projection of this

newmann of this

for this reaction, hydroboratin, what are the general rules

1)Boron ends up on less hindered end

2)oxidation occurs with retention of configuration

why is this the ratio

small group is hydrogen, 90 degrees is the biggest group, so bc Hydrogen is sterically less hindered, buti in the equillibirum, theres a bit of steric clash with Ph and the BH2 group so hence disfavoured.

two get newmann to look like molecule, the substituents shifted one to the left. so OH took H position, H took Me posotion Me took OH position

advantage of using 9BBN

its more selective for some major isomer of product by >95: >5 regioisomeric control

this makes

mostly stays the same with the ch and h flipping

whats going on here

draw the ring as a circle and this is whats favoured due to less teric clash

explain this

same concept but remember to switch substituents around

how do we get from reactant to product

whats the prodcuts for these and its reasoning

mCPBA is the same reason for the one before, the one below

the onzoloysis mechanism

reminder of how sn2 reactions go which then expains SE2 reactions

metal or psuedo group (silicon) attacks the electrophile

we can see in SE2 reaction the silicon group has gone, whats happening here

the p orbital is adjacent to the silicon carbon on the adjacent carbon the p orbital of sillyl is positive bringing greater stability bc sillyl is electropositive. This is beta silyl carbon

Draw out the attack of TiCl4

why is this the ratio

theres steric clash in the tbu and methyl. the substituents swap. the enantiomer is made with diff starting material

whats chelation control

something reacting 90 degrees to alkene

why is this the case

steric hindrance in disfavoured one by the me groups

why is this much less diastereoselective

because h and me do have a steric clash, its still not by match

why is this the major

pseudoaxial

whys this the major

why is this favoured

because the r group is near H which is a small substituent