Can u pls explain me this 2 lines ..?

OH group show chelation effect with Zn Simun so it direct the incoming group. So -OH &. CH2 group has same stereo

In 2nd reaction CH3 show steric repulsion. So due to steric repulsion CH2 is in dash position i.e trans

chelation effect means ?

OH binds with Zn Simun. This is chelation effect.

So it helps in bringing the reactant closer. Chelation happen as OH has lone pair.

Yes Simun 😊

Don't mistake chelation as a bond. It is just a sort of interaction like you see in intermolecular hydrogen bonding.

yes sir tq sir

it is a steriospecific reaction na so why in CH3 case give opposite sterio according to reactent

As I have explained earlier also CH3 can't show such chelation so it shows repulsion to the incoming group.

Stereospecific means either Trans or cis whatever may be the product if cis then 100% cis & if trans then 100 %trans

seee

This is what I am saying

if you got cis then 💯 % cis

got it Simun

yes sir

in this case stereochemistry of ether is same as in OH i.e., wedge. because simmon smith carbene attacks towards polar group because it forms H bonding with zn

I can't able to understand this sir

can u simply explain me about this lines pls ..

yes wait..

ok sir

but sir how epoxidation occurs here only cyclopropane formsna

yes sir ..it ok sir

check now

I got it sir tq sir 😊🙏🙏

got it now. if OH, OR groups are given then the stereochemistry of cyclopropane will be as such in the polar groups

if othere groups then reverse the stereo

👍😊😊

but sir this reaction is steriospecific na so cis give cis ..and trans give trans products so same sterio na

also given like this sir

yes, but here stereochemistry not given in the reactant

it's according to OH group. here H is dash mean cyclopropyl will be on wedge

yes sir and it is steriospecific so it sterio is always same na

sterio of reactant and products

no Simun stereo depends on only group attached on allyllic position

ohhh so sir in this 2 case it give trans trans and cis Cis why

yes, in this case cis give cis. and trans give trans

why sir

here concerted mechanism takes place.

sir I m very much confused about this reaction 😔

some time its sterio will be difff some time same ...

why Simun. it's not complicated. just remember if stereochemistry is given in the reactant then it mantain in the product.

like the pic of Oh I have send na

yes, in last picture you sent

but sir the pic u send in which CH3 in dash and product in wedge

yes, but it is cyclic alkene. it is not cis or trans

ok sir

try some questions the ask if any problem 😊

and now this sir

this is just like as in OH

but sir why cyclopropanation canine takes place at other double bond

nucleophilc alkene prefer cyclopropane. here alkene attached with ERG is more nucleophilc than other so cyclopropanatin takes place on this alkene

sir cyclopropanation why not takes place in this double bond

can you share it in new query

ok sir