Metal Free, Direct and Selective Deoxygenation of α-Hydroxy Carbonyl Compounds: Access to α,α-Diaryl Carbonyl Compounds
作者:Sandeep、Paloth Venugopalan、Anil Kumar
DOI:10.1002/ejoc.202000142
日期:2020.5.10
A variety of α‐hydroxy‐α,α‐diaryl carbonylcompounds are selectively deoxygenated to give an important class of α,α‐diaryl carbonylcompounds using catalytic amount of aqueous HClO4 (70 %) and triethylsilane as hydride source.
Selective Carbonyl−C(sp<sup>3</sup>) Bond Cleavage To Construct Ynamides, Ynoates, and Ynones by Photoredox Catalysis
作者:Kunfang Jia、Yue Pan、Yiyun Chen
DOI:10.1002/anie.201611897
日期:2017.2.20
Carbon–carbonbondcleavage/functionalization is synthetically valuable, and selective carbonyl−C(sp3) bondcleavage/alkynylation presents a new perspective in constructing ynamides, ynoates, and ynones. Reported here is the first alkoxyl‐radical‐enabled carbonyl−C(sp3) bondcleavage/alkynylation reaction by photoredox catalysis. The use of novel cyclic iodine(III) reagents are essential for β‐carbonyl
A Highly Efficient Friedel–Crafts Reaction of Tertiary α‐Hydroxyesters or α‐Hydroxyketones to α‐Quaternary Esters or Ketones
作者:Long Chen、Jian Zhou
DOI:10.1002/asia.201200693
日期:2012.11
A catalytic Friedel–Crafts arylation of α‐hydroxyesters or α‐hydroxyketones with electron‐rich aromatic compounds to furnish α‐quaternaryesters/ketones has been developed. The cheap and easy to handle catalyst HClO4 (70 %, aq) was identified as a powerful catalyst for this arylation reaction.
The intermolecular reductive coupling of aromatic ketones with acylimidazoles was effected by electroreduction in the presence of chlorotrimethylsilane and gave α-trimethylsiloxy ketones and esters. The best result was obtained using Bu4NPF6 as a supporting electrolyte and a Pb cathode in THF. The α-trimethylsiloxy-containing products were transformed to the corresponding α-hydroxy ketones and esters
proposals of α-carbonyl cation intermediates have been driven by chemical intuition and indirect evidence. Recently, wide interest in α-carbonyl cation chemistry has opened new gates to prepare α-functionalized carbonyl compounds. Though these intrinsically unstable carbocations are formed under forcing conditions (e.g., in a strong acid medium), their fleeting existence prohibits direct observation