75359-74-9Relevant academic research and scientific papers
A Silyl Enol Ether Variation of the Robinson Annulation
Huffman, John W.,Potnis, Shailesh M.,Satish, Amruthur V.
, p. 4266 - 4270 (1985)
The Lewis acid catalyzed reaction of regioselectively generated silyl enol ethers with vinyl ketones has been explored as an alternative to the Robinson annulation sequence.Alkylation of the trimethylsilyl enol ethers of cyclohexanone, 2-methylcyclohexanone, and 2,3-dimethylcyclohexanone with ethyl vinyl ketone, 3-penten-2-one, and methyl vinyl ketone ethylene ketal gave a series of 1,5-diketones.Cyclization of the diketones affords 2-octalones in fair to good overall yield.This procedure has been used to prepare in good yield 5,10-dimethyl-Δ1(9)-2-octalone, an important intermediate for sesquiterpene synthesis, with a cis/trans ratio of 3 to 1.Alkylation of the trimethylsilyl enol ether of isobutyraldehyde with 3-penten-2-one, methyl vinyl ketone, and its ethylene ketal followed by cyclization affords 4,4,5-trimethyl- and 4,4-dimethyl-2-cyclohexen-1-one.This method has been employed in the synthesis of 5-(hydroxymethyl)-2,4,4-trimethyl-2-cyclohexen-1-one, a potential synthon for ring A of the taxane diterpenes.
Regioselective Robinson annulation realized by the combined use of lithium enolates and aluminum tris(2,6-diphenylphenoxide) (ATPH)
Saito, Susumu,Shimada, Itsuro,Takamori, Yusuke,Tanaka, Michiaki,Maruoka, Keiji,Yamamoto, Hisashi
, p. 1671 - 1681 (2007/10/03)
Michael addition of lithium enolates derived from ketones to a variety of a, β-unsaturated ketones was realized in the presence of aluminum tris(2,6-diphenylphenoxide) (ATPH). In this reaction, ATPH can be used as a carbonyl protector of a, β-unsaturated carbonyl substrates upon complexation, which facilitates the regioselective 1,4-addition of lithium enolates to Michael acceptors. Similarly, dianions of β-dicarbonyl compounds undergo Michael addition smoothly using ATPH as an effective promoter of the reaction. Subsequent regioselective, intramolecular aldol condensation was also demonstrated, leading to bicyclic carbon ring systems. Such systems are difficult to obtain by the Robinson annulation usually performed in protic media.
Organotin Triflate as Practical Catalyst for Michael Addition of Enol Silyl Ethers
Sato, Tsuneo,Wakahara, Yoshiyuki,Otera, Junzo,Nozaki, Hitosi
, p. 9773 - 9782 (2007/10/02)
Dibutyltin bis(triflate) is a mild Lewis acid which catalyzes clean Michael addition of enol silyl ethers.The new catalyst allows to employ various labile acceptors such as methyl vinyl ketone and 2-cyclopentenone which do not undergo smooth reaction with
Organotin triflates as functional Lewis acids. A new entry to simple and efficient Robinson annulation
Sato, Tsuneo,Wakahara, Yoshiyuki,Otera, Junzo,Nozaki, Hitosi
, p. 1581 - 1584 (2007/10/02)
An efficient Robinson annulation has been established through the Michael addition of enol silyl ethers to α-enones catalyzed by dibutyltinbis(triflate) followed by the MeONa-mediated intramolecular aldol condensation of the adducts.
LATENT ACETONYLATION OF α,β-ENONES WITH ALLYLTRIMETHYLSILANE OR 2-METHYL-2-PROPENYLTRIMETHYLSILANE: SYNTHESIS OF 1,5-DIKETONES AND ANNELATION TO FUSED CYCLOHEXENONES
Hosomi, Akira,Kobayashi, Hiroshi,Sakurai, Hideki
, p. 955 - 958 (2007/10/02)
Acetonylation of α,β-enones can be achieved by either with (2-methyl-2-propenyl)trimethylsilane or with allyltrimethylsilane followed by oxidative cleavage of the double bond or by the Wacker reaction, respectively.Annelation of the 1,5-diketones is also
Novel Synthetic Reactions Using Bis(2,2,2-trifluoroethoxy)diorganosulfuranes
Kitazume, Tomoya,Ishikawa, Nobuo
, p. 2064 - 2066 (2007/10/02)
Alkoxy- or acyloxysulfuranes prepared in situ by the ligand exchange of bis(2,2,2-trifluoroethoxy)diorganosulfuranes with alcohols or carboxylic acids were found to behave as a potential alkylating or acylating reagent for the preparation of unsymmetrical sulfides, ketones, and esters.
