36322-03-9Relevant articles and documents
Synthesis, Structural Characterization, and Reactivity of a Fluorene-Based Calcium Oxycyclopentadienide Complex
Wei, Baosheng,Li, Heng,Zhang, Wen-Xiong,Xi, Zhenfeng
, p. 1339 - 1344 (2015)
Direct deprotonation of 9-fluorenol with Ca[N(SiMe3)2]2 efficiently generated a fluorene-based calcium oxycyclopentadienide complex, which is the first alkaline earth metal complex containing an oxycyclopentadienyl dianion ligand. The η5, η1, and η2 interactions between the oxycyclopentadienyl dianion ligand and the calcium center were observed in the solid state. The calcium oxycyclopentadienide complex displayed reductive character and multiple reactive sites. Its reactivity toward a range of electrophiles, especially acid chlorides, was investigated and discussed in detail. A wide variety of fluorene derivatives were synthesized. (Chemical Equation Presented).
Manganese-Catalyzed Synthesis of Quaternary Peroxides: Application in Catalytic Deperoxidation and Rearrangement Reactions
Chaudhari, Moreshwar B.,Gnanaprakasam, Boopathy,Shaikh, Moseen A.,Ubale, Akash S.
, p. 10488 - 10503 (2020/09/23)
Highly efficient, selective, and direct C-H peroxidation of 9-substituted fluorenes has been achieved using a Mn-2,2′-bipyridine catalyst via radical-radical cross-coupling. Moreover, this method effectively promotes the vicinal bisperoxidation of sterically hindered various substituted arylidene-9H-fluorene/arylideneindolin-2-one derivatives to afford highly substituted bisperoxides with high selectivity over the oxidative cleavage of Ca C bond that usually forms the ketone of an aldehyde. Furthermore, a new approach for the synthesis of (Z)-6-benzylidene-6H-benzo[c]chromene has been achieved via an acid-catalyzed skeletal rearrangement of these peroxides. For the first time, unlike O-O bond cleavage, reductive C-O bond cleavage in peroxides using the Pd catalyst and H2 is described, which enables the reversible reaction to afford exclusively deperoxidized products. A detailed mechanism for peroxidation, molecular rearrangement, and deperoxidation has been proposed with preliminary experimental evidences.
Aldehydes as alkyl carbanion equivalents for additions to carbonyl compounds
Wang, Haining,Dai, Xi-Jie,Li, Chao-Jun
, p. 374 - 378 (2017/04/03)
Nucleophilic addition reactions of organometallic reagents to carbonyl compounds for carbon-carbon bond construction have played a pivotal role in modern chemistry. However, this reaction's reliance on petroleum-derived chemical feedstocks and a stoichiometric quantity of metal have prompted the development of many carbanion equivalents and catalytic metal alternatives. Here, we show that naturally occurring carbonyls can be used as latent alkyl carbanion equivalents for additions to carbonyl compounds, via reductive polarity reversal. Such 'umpolung' reactivity is facilitated by a ruthenium catalyst and diphosphine ligand under mild conditions, delivering synthetically valuable secondary and tertiary alcohols in up to 98% yield. The unique chemoselectivity exhibited by carbonyl-derived carbanion equivalents is demonstrated by their tolerance to protic reaction media and good functional group compatibility. Enantioenriched tertiary alcohols can also be accessed with the aid of chiral ligands, albeit with moderate stereocontrol. Such carbonyl-derived carbanion equivalents are anticipated to find broad utility in chemical bond formation.
