＜正＞ Allenes are three carbon functional groups possessing two perpendicular π-orbitals. Their unique reaction ...
MA, Sheng-Ming YU, Zhan-Qian
( State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences , Shanghai 200032)
＜正＞ The reaction of diethyl malonate with various substituted 1,2-allenic ketone can be catalyzed by 10% of K2...
MA, Sheng-Ming YU, Shi-Chao
(State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences , Shanghai 200032)
Organoboronic acids enjoy high prestige in the metal-catalyzed C-C bond formations. The most notable progress is the rhodium- and nickel-catalyzed conjugate addition with unsaturated carbon-carbon bond, aldehydes, N-sulfonyl imines reported by Miyaura, Hayashi and Shirakawa.[1]……
5-Hydroxyfuran-2(5H)ones are an important class of compounds because they often occur in natural products and exhibit a broad range of biological activities. Recently, much attention has been focused on the efficient and di verse synthesis of these compounds, particularly 4-halo-5-hydroxy-2(5H)-furanones. The typical synthetic strategies include acid catalyzed cyclization of ketonic acids, auto oxidation of corresponding lactone in air, rearrangement reactions of α-phenylsulphinylacrylates, oxidation with chromium trioxide in acetic acid, and bromination-hydrolysis of α ,β-butanolides. Herein, we wish to report that 4-halo-5-hydroxyfuran-2(5H)-ones were synthesized via the efficient sequential halolactonization-hydroxylation reaction of 4-aryl-2,3-allenoic acids with I2 or CuX2 (X = Br or Cl) inmoderate to good yields.……
The reaction of diethyl malonate with various substituted 1,2-allenic ketone can be catalyzed by 10% of K2CO3leading to polyfunctionalized β, γ-unsaturated enones 3 or 4. With 3-unsaturated 1-substituted-1, 2-allenic ketones, the highly selective formation of β, γ-unsaturated enones 4 was observed; with 1,2-allenic ketones with one or two γ-substituents, only β, γ-unsaturated enones 3 with an unmigrated carbon-carbon double bond were produced; with γ-monosubstituted-1,2-allenic ketones the corresponding (E)-3 were formed highly selectively; with propadienyl ketones, a mixture of β, γ-unsaturated enones 3 and 4 were formed.……
Allenes are three carbon functional groups possessing two perpendicular π-orbitals. Their unique reaction be havior is spread over three carbon atoms, which shows great potential in organic synthesis in terms of chirality transfer and diversity, as a result of the axial chirality as well as the substituent-loading capability. Recently, we devoted ourselves to establish a new area of oxidative cyclization-dimerization reactions between two functionalized allenes to give interesting bicyclic compounds in a single step. The formidable challenges are to match the reactivities of two allenes, and regenerate the catalyst, which would be reduced after reductive-elimination. In this paper we wish to disclose our recent studies on the synthesis of bi-butenolides from oxidative cyclization self-coupling reaction of 2,3 allenoic acids, in which a new system (PdCl2/RI/air) for regeneration of the palladium(Ⅱ) species was observed.……
A chiron approach-based enantioselective synthesis of designed tricyclic tyrosine analogue D-2 was developed. A SmI2-mediated free radical cyclization, an intramolecular Friedel-Crafts reaction and an intramolecular Mannich reaction served as key steps. These key steps were optimized and repeated in good yields. All the stereochemistries in the synthesis were established and confirmed.
Optically active 1-aryl-2,3-allenols were obtained via CCL-mediated kinetic resolution of the racemic allenols. The substitution pattern of the aromatic ring, regarding to both the type of the substituent and its position on the aromatic ring, was found to be critical for the kinetic resolution of 1-aryl-2,3-allenols.
＜正＞ 5-Hydroxyfuran-2（5H）ones are an important class of compounds because they often occur in natural productsa...
MA, Sheng-Ming WU, Bin SHI, Zhang-Jie
(State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences , Shanghai 200032)
