使用核爱性源进行α--β-硫基碳化合物的光催化合成

α,β-Unsaturated carbonyl compounds are molecules bearing a carbonyl and alkene functionality in conjugation with each other. The conjugation in the molecule leads to three resonance structures. The hybrid form exhibits two probable electrophilic sites: the carbonyl carbon and the β carbon.

α-Substituted ketones or aldehydes can be synthesized from enamines by the Stork enamine reaction, named after its pioneer Gilbert Stork. Enamines are useful synthetic intermediates where the lone pair on nitrogen is in conjugation with the C=C bond. They resemble enolate ions, as the resonance forms of both species have a nucleophilic α carbon.

Nucleophilic substitution in α-halocarbonyl compounds can be achieved via an SN2 pathway. The reaction in α-haloketones is generally carried out with less basic nucleophiles. The use of strong basic nucleophiles leads to the generation of α-haloenolate ions, which often participate in other side reactions.

The carbonyl carbon in an aldehyde or ketone is the site of a nucleophilic attack due to its electron-deficient nature. Depending on the strength of the incoming nucleophile, the reaction occurs via different mechanistic pathways.
A stronger nucleophile can directly attack the electrophilic center, the carbonyl carbon. The HOMO orbital of the nucleophile interacts with the LUMO (π* antibonding) orbital present on the carbonyl carbon. This interaction breaks the π bond and shifts the π...

Reduction is a simple strategy to convert a carbonyl group to a hydroxyl group. The three major pathways to reduce carbonyls to alcohols are catalytic hydrogenation, hydride reduction, and borane reduction.
Catalytic hydrogenation is similar to the reduction of an alkene or alkyne by adding H2 across the pi bond in the presence of transition metal catalysts like Raney Ni, Pd–C, Pt, or Ru. Aldehydes and ketones can be reduced by this method, often under mild to moderate heat (25–100°C) and...

Grignard reagents are one of the most commonly used reagents used to synthesize alcohols from carbonyl compounds. Grignard reagents are organomagnesium halides with a highly polar carbon–magnesium bond. Due to the partial ionic nature of the C–Mg bond, the carbon functions as a strong nucleophile and attacks electrophiles like carbonyl carbon.
Magnesium from the reagent coordinates with carbonyl oxygen, further reducing the carbonyl carbon's electron density. Thus, the...