75351-30-3Relevant academic research and scientific papers
Total Synthesis of (?)-Glaucocalyxin A
Guo, Jiuzhou,Jia, Yanxing,Li, Bo,Ma, Weihao,Pitchakuntla, Mallesham
supporting information, p. 15195 - 15198 (2020/06/30)
A practically useful method for the formation of the highly oxygenated bicyclo[3.2.1]octane ring system through Mn(OAc)3-mediated radical cyclization of alkynyl ketones was developed, which opens up a new avenue for the total synthesis of a number of highly oxidized diterpenoids. Application of this method enabled the first total synthesis of (?)-glaucocalyxin A. Other salient features of the synthesis include a highly enantioselective conjugate addition/acylation cascade reaction, a Yamamoto aldol reaction, and an intramolecular Diels–Alder reaction to assemble the A/B ring system.
N-Heterocyclic carbenes as ligands in palladium-catalyzed Tsuji-Trost allylic substitution
Sato, Yoshihiro,Yoshino, Taro,Mori, Miwako
, p. 5753 - 5758 (2007/10/03)
A Pd(0)-catalyzed allylic substitution (i.e., Tsuji-Trost reaction) using N-heterocyclic carbene as a ligand was investigated. It has been proven that an imidazolium salt 2d having bulky aromatic rings attached to the nitrogens in its imidazol-2-ylidene skeleton is suitable as a ligand precursor and that a Pd2dba3-imidazolium salt 2d-Cs2CO3 system is highly efficient for producing a Pd-NHC catalyst in this reaction. Allylic substitution using a Pd-NHC complex differed from that using a Pd-phosphine complex as follows: (1) the reaction using a Pd-NHC complex required elevated temperature (50 °C or reflux in THF), (2) allylic carbonates were inert to a Pd-NHC complex, and (3) nitrogen nucleophiles such as sulfonamide and amine did not react with allylic acetate. It was also found that allylic substitution with a soft nucleophile using a Pd-NHC catalyst proceeds via overall retention of configuration to give the product in a stereospecific manner, the stereochemical reaction course obviously being the same as that of the reaction using a Pd-phosphine complex.
COMPLETE RETENTION OF CHIRALITY IN THE PALLADIUM CATALYZED CYCLIZATION OF METHYL (R)-3-OXO-7-METHOXYCARBONYLOXY)-8-NONENOATE
Yamamoto, Keiji,Deguchi, Ryoji,Ogimura, Yoshinobu,Tsuji, Jiro
, p. 1657 - 1660 (2007/10/02)
Optically active methyl (R)-3-oxo-7-methoxycarbonyloxy)-8-nonenoate (1) underwent intramolecular allylation catalyzed by Pd(OAc)2-dppe in THF at room temperature to give racemic 3-vinyl-2-methoxy-carbonylcyclohexanone (3), whereas similar palladium-cataly
PALLADIUM-CATALYZED ASYMMETRIC CYCLIZATION OF METHYL (E)-OXO-9-PHENOXY-7-NONENOATE AND ITS ANALOGS
Yamamoto, Keiji,Tsuji, Jiro
, p. 3089 - 3092 (2007/10/02)
Asymmetric cyclizations of methyl (E)-3-oxo-9-phenoxy-7-nonenoate (1) or methyl (E)-3-oxo-9-(methoxycarbonyl)oxy-7-nonenoate (4) without added base were carried out in the presence of a catalytic amount of palladium(II) acetate and chiral diphosphine as l
PREPARATION OF FIVE- AND SIX- MEMBERED CYCLIC KETONES BY THE PALLADIUM-CATALYZED CYCLIZATION REACTION. APPLICATION TO METHYL DIHYDROJASMONATE SYNTHESIS
Tsuji, Jiro,Kobayashi, Yuichi,Kataoka, Hideaki,Takahashi, Takashi
, p. 1475 - 1478 (2007/10/02)
Methyl 3-oxo-8-phenoxy-6-octenoate (1) was cyclized using Pd(OAc)2-PPh3 as a catalyst to give 2-carbomethoxy-3-vinylcyclopentanone (2) and 2-carbomethoxy-4-cycloheptenone (3).The former was the main product in acetonitrile. 2-Alkylated 3-oxo-8-phenoxy-6-octenoates were converted mainly to the five-membered ketones.Based on this cyclization method, methyl dihydrojasmonate (8) was prepared from methyl 2-pentyl-3-oxo-8-phenoxy-6-octenoate (5).Methyl 3-oxo-9-phenoxy-7-nonenoate (10) was subjected to the palladium-catalysed cyclization to afford 2-carbomethoxy-3-vinylcyclohexanone (11) selectively without forming the eight membered ketone (12).
