yes you can take propynide ion in place of GR and then do reduction using Lindlar's catalyst to get cis- alkene

Thank you! Because one of the substituents, is cis-alkene, is it possible to use alkyne (HCtriplebondC-Na+) with water to form alkyne on wedge, then use H2 and lindlars catalyst to get cis-alkene?

Protect only the primary alcohol (so oxidation doesn't hit it)
Use OsO4 tp get syn diol
Do oxidation using PCC
Deprotect alcohol

Step 1: Convert the starting alcohol into the ethyl ether (OEt).

Reagents (typical): EtI (or EtBr), base (e.g., NaH ), suitable solvent.

Outcome: ROH → ROEt (no change to the epoxide stereochemistry).
2) use carbanion from Grignard reagent to open the ring with correct sterochemistry
3) Conver alcohol so formed into desired ether by williamson's synthesis.

Step-by-step mechanism (acid-catalyzed acetal hydrolysis of cyclic acetal
)

Protonation of one acetal oxygen (O gets H⁺)
This makes that C–O bond easier to break.

C–O bond cleavage (ring opening) → oxocarbenium ion
The acetal carbon becomes an oxocarbenium-like electrophile (strongly activated carbon attached to oxygen).

Water attacks the oxocarbenium carbon
Water adds to that carbon, giving a protonated hemiacetal intermediate.

Proton transfer / deprotonation
This neutralizes the intermediate and prepares the second C–O group to leave.

Protonation of the second acetal oxygen
Now the remaining "OR" part becomes a good leaving group.

Second C–O cleavage forms the carbonyl (aldehyde)
As the second C–O bond breaks, the C=O (aldehyde) is re-formed, and the second oxygen becomes an alcohol (–OH).

Deprotonation gives the final neutral product

LDA makes an anion (base step)

The epoxysilane rearranges (ring opens + Si moves to O)

That rearranged anion attacks MeI → methylation

I would love some help with these, thank you so much!

Hello, I would appreciate some help with this!

Hello, I would appreciate some help with this!

Hello, I would appreciate some help with this!