Addition of Carbenes to Alkenes A carbene (R2C:)is a neutral molecule containing a CI- divalent carbon with only 6 electrons in its valence shell Strong base abstracts the chloroform proton,leaving behind the electron Carbenes are highly reactive, pair from the C-H bond and forming electron-deficient and the trichloromethanide anion. behaves as an electrophile C-C:- +H,0 Addition of carbene to alkene occurs in a single step Trichloromethanide anion R R Loss of a chloride ion and associated R electrons from the C-Cl bonds yields C=C the neutral dichlorocarbene. C R C:+Cl An alkene A carbene A cvclopropane C Addition of Carbenes to Alkenes „ A carbene (R 2 C:) is a neutral molecule containing a divalent carbon with only 6 electrons in its valence shell „ Carbenes are highly reactive, electron-deficient and behaves as an electrophile „ Addition of carbene to alkene occurs in a single step