new sort of doubts..

it wud form a inserted product .....i.e the carbond on tghe double bond will ....the dichloro carbene wud form an bond withh both atoms ..of double bond!

mostly!

The addition of carbenes to alkenes is principally to make cyclopropanes.

:CCl₂ is generated by t-BuO^-K⁺ and CHCl₃

the dichlorocyclopropanes can be reduce to hydrocarbons.

*** the addition of dichlorocarbenes, like that of singlet methylene, is stereoselective and stereospecific and syn.

The single product formed here is generated in two steps:

1) attack on chloroform by a very strong base
2) addition on alkene

for reference page 512-513 Morrison-Boyd

Adding a little more, the generation of carbene is caused by ALPHA-elimination in chloroform via a base. (Normal eliminations are beta eliminations)