36773-67-8Relevant articles and documents
C-O-bond cleavage of esters with a naphthyl group in the higher triplet excited state during two-color two-laser flash photolysis
Cai, Xichen,Sakamoto, Masanori,Yamaji, Minoru,Fujitsuka, Mamoru,Majima, Tetsuro
, p. 3143 - 3149 (2007)
A C-O-bond cleavage of esters having a naphthyl group, NpCO-OR and RCO-ONp (Np = α- and βnaphthyl (αNp and βNp, respectively), R = Ph and Me), was found during the two-color two-laser flash photolysis in acetonitrile. The C-O-bond cleavage occurred when NpCO-OR and RCO-ONp were excited to the singlet excited states (S1). On the other hand, no reaction occurred from the lowest triplet excited states (T 1). When NpCO-OR(T1) and RCO-ONp(T1) were excited to the higher triplet excited states (Tn) using the second laser during the two-color two-laser flash photolysis, the C-O-bond cleavage occurred. The C-O-bond cleavage quantum yield (Φ) was estimated from the plots of the T1state esters disappeared within a laser flash versus the second laser intensities. The C-O-bond cleavage in βNpCO- OPh(Tn) occurred more efficiently than in αNpCO- OPh(Tn) and that in PhCO-OβNp(Tn) occurred more efficiently than in PhCO-OαNp(Tn). The Φ value for ester with Ph and β-Np groups was larger than that for ester with Ph and α-Np groups. The Φ value for MeCO-OαNp(T n) was similar to those for PhCO-ONp(Tn), while that for MeCO-OβNp(Tn) was much smaller than those for PhCO-ONp(T n) and MeCO-OαNp(Tn). On the other hand, no C-O-bond cleavage was observed in NpCO-OMe(Tn). The Φ value depended on the characters of the groups (Np, Ph, and Me) on the ester. Whether R is Ph or Me with or without π electron, respectively, is important for the C-O-bond cleavage. In other words, electronic delocalization of the T n state including Np and ester groups is necessary for the occurrence of the C-O-bond cleavage in NpCO-OR(Tn) and RCO-ONp(Tn).
Fluoride anion-initiated bis-trifluoromethylation of phenyl aromatic carboxylates with (trifluoromethyl)trimethylsilane
Takahashi, Kenjiro,Ano, Yusuke,Chatani, Naoto
supporting information, p. 11661 - 11664 (2020/10/19)
The fluoride anion-initiated reaction of phenyl aromatic carboxylates with (trifluoromethyl)trimethylsilane (Me3SiCF3) that results in the formation of O-silyl-protected 2-aryl-1,1,1,3,3,3-hexafluoroisopropanols is reported. A phenoxide anion, generated during the trifluoromethylation of the phenyl carboxylate, also activates the Me3SiCF3, which permits a catalytic amount of the fluoride anion source to be used. Various functional groups, which can be used for further elaboration, are tolerated in the reaction.
Decarbonylative Methylation of Aromatic Esters by a Nickel Catalyst
Okita, Toshimasa,Muto, Kei,Yamaguchi, Junichiro
, p. 3132 - 3135 (2018/05/28)
A Ni-catalyzed decarbonylative methylation of aromatic esters was achieved using methylaluminums as methylating agents. Dimethylaluminum chlorides uniquely worked as the methyl source. Because of the Lewis acidity of aluminum reagents, less reactive alkyl esters could also undergo the present methylation. By controlling the Lewis acidity of aluminum reagents, a chemoselective decarbonylative cross-coupling between alkyl esters and phenyl esters was successful.
