Tebbes reagent
It is used as alkenytion.
Titanium aluminum based complex used as we know aldehyde and ketone can be methylelated via witting rxn but Ester and amide can not so for them we have tables reagent
Witting reagent give cis or Trans alkene when
Trans when ch–ewg has this
Cis when ch–ch3 Has this
Metathesis rxn is applied to 2 alkene system refers to Trans position of the alkene carbon atom
The rxn is catalysed by by various transition metal alkylidine (carbene) complex particularly based on Ru ruthenium , molybdenum complex
It follows 2+2cyclo addition via 4 membered cyclic system
It is an excellent way to form difficult ring size such as 8,9,10,11,12 and so on