21441-45-2Relevant academic research and scientific papers
CO2-activation for γ-butyrolactones and its application in the total synthesis of (±)-heteroplexisolide e
Li, Suhua,Ma, Shengming
, p. 2411 - 2418 (2012/10/29)
An efficient nickel(0)-catalyzed highly regio- and stereoselective hydrocarboxylation of homopropargylic alcohols with ZnEt2 in the presence of CO2 (1 atm, balloon) to synthesize α-alkylidene- γ-butyrolactones is described. The catal
A convenient synthesis of γ-methyl α-(alkylidene)-γ- butyrolactones
Shet, Jyoti B.,Amonkar, Chandan P.,Nadkarni, Vishnu S.,Tilve, Santosh G.
, p. 1505 - 1508 (2007/10/03)
γ-Methyl-α-(alkylidene substituted)-γ-butyrolactones have been synthesized in two steps. The anion of allyl phosphonate 1 is condensed with different carbonyl compounds to afford α,β-unsaturated esters 2a-g which are cyclised using 6N HCl to give title co
Spiroaziridines from 4-substituted α-ylidene-γ-butyro lactones
Gasperi, Tecla,Loreto, M. Antonietta,Migliorini, Antonella,Tardella, Paolo A.
, p. 1447 - 1454 (2007/10/03)
4-Substituted α-ylidene-γ-butyrolactones produce N-ethoxycarbonyl-spiroaziridino γ-lactone diastereomers on treatment with NsONHCO2Et and CaO. A good stereofacial preference is observed when the ring substituent is a phenyl group. These product
Efficient synthesis of α-benzylidene-γ-methyl-γ-butyrolactones
Mali, Raghao S.,Babu, Kantipudi N.
, p. 3525 - 3531 (2007/10/03)
A concise synthesis of α-benzylidene-γ-methyl-γ-butyrolactones 5a - g from substituted benzaldehydes is described. Compounds 1a - g on reaction with phosphorane 2, provide the pentenoates 3a - g, which can be hydrolyzed to the acids 4a - g. The latter are cyclized to the corresponding butyrolactones 5a - g in excellent yields. The pentenoates 3a - g, on acid catalyzed cyclization, also provide 5a - g in very high yields.
Synthesis of substituted α-methylene-γ-butyrolactones from chloroformates via palladium catalysed cyclisation-anion capture
Grigg,Savic
, p. 2381 - 2382 (2007/10/03)
Cyclisation of chloroformates onto proximate alkyne functionality in the presence of a Pd(0) catalyst followed by anion capture affords α-methylene-γ-butyrolactone derivatives in moderate to good yields.
Tungsten(II)-carbene complex functions as a dicationic synthon: Efficient constructions of furan and pyran frameworks from readily available α,δ- and α,ε-alkynols
Liang, Kwei-Wen,Li, Wen-Tai,Peng, Shie-Ming,Wang, Sue-Lein,Liu, Rai-Shung
, p. 4404 - 4412 (2007/10/03)
Treatment of tungsten-η1-α,δ- and -η1-α,ε-alkynols 4-6 with RCHO/BF3 · Et2O (R = alkyl, aryl) in cold diethyl ether effected cycloalkenation reaction, yielding tungsten-η1-furylidene and -η1- pyrylidene salts in excellent yields (>95%). The structures of these oxacarbeniums were elucidated through X-ray diffraction studies of the representative compounds 7 and 8 in addition to standard NMR and IR spectral data. In contrast with conventional metal carbeniums, these tungsten oxacarbeniums reacted with two molecules of nucleophiles such as H20, NaBH3CN, and Grignard reagents, resulting in α,α-double addition reactions to afford furan and pyran derivatives in good yields. In the hydride case, unsymmetric α,α-double addition of η1-furylidenium salts was achieved via treatment with NaBH4/MeOH. Organocuprates also effected double alkylations of these salts but in a distinct 1,3-addition pathway. The reactions of these oxacarbeniums with CH2N2 were examined; the outcome depends on their vinyl substituents. When the substituent is an aliphatic group, the carbenium species undergo highly diastereoselective cyclopropanation with CH2N2. For an aryl substituent, the reaction with CH2N2 yielded a new tungsten oxacarbenium with a significantly altered structure; in this case 13C- and 2H-labeling experiments were performed to elucidate the reaction mechanism.
POLARIZED KETENE DITHIOACETALS 63. STEREOSELECTIVE SYNTHESIS OF Α-YLIDENE-Γ-BUTYROLACTONES
Datta, Apurba,Ila, Hiriyakkanavar,Junjappa, Hiriyakkanavar
, p. 5367 - 5374 (2007/10/02)
A facile method for highly stereoselective synthesis of α-arylidene (4a-d, 4f-h and 4j) and α-ethylidene (4e,4i)-γ-butyrolactones has been developed by acid catalyzed lactonization of the corresponding α-ylidene-γ,δ-unsaturated esters 3a-j.The required es
A Two-Step Preparation of α-Alkylidene γ-Lactones from γ-Lactones: A Synthesis of (+/-)-Ancepsenolide
Larson, Gerald L.,Perez, Rosa M. Betancourt de
, p. 5257 - 5260 (2007/10/02)
γ-Butyrolactone, γ-valerolactone, and the cis lactone of 2-hydroxycyclohexaneacetic acid have been C-silylated via their respective lithium enolates with diphenylmethylchlorosilane.The resulting α-silylated γ-lactones can be deprotonated and condensed with aldehydes and ketones to give α-alkylidene γ-lactones in moderate to excellent yield.The enolate of the α-diphenylmethylsilyl cis lactone of 2-hydroxycyclohexaneacetic acid condensed with 1-butanal but not with benzaldehyde or acetaldehyde.
