- Source: Carbenoid
In chemistry a carbenoid is a reactive intermediate that shares reaction characteristics with a carbene. In the Simmons–Smith reaction the carbenoid intermediate is a zinc / iodine complex that takes the form of
I-CH2-Zn-I
This complex reacts with an alkene to form a cyclopropane just as a carbene would do.
Carbenoids appear as intermediates in many other reactions. In one system a carbenoid chloroalkyllithium reagent is prepared in situ from a sulfoxide and t-BuLi which reacts the boronic ester to give an ate complex. The ate complex undergoes a 1,2-metallate rearrangement to give the homologated product, which is then further oxidised to a secondary alcohol.
The enantiopurity of the chiral sulfoxide is preserved in the ultimate product after oxidation of the boronic ester to the alcohol indicating that a true carbene was never involved in the sequence.
See also
The silicon pendant: Silylenoids
References
Kata Kunci Pencarian:
- Carbenoid
- Simmons–Smith reaction
- Johnson–Corey–Chaykovsky reaction
- Clemmensen reduction
- Carbene
- Schiff base
- Ring expansion and contraction
- Reactive intermediate
- Metal-catalyzed cyclopropanations
- Vinylidene group
