20549-39-7Relevant academic research and scientific papers
Preparation of the first polymeric, chelating proton donors and their use in diastereoselective protonations of chiral enolates
Krause, Norbert,Mackenstedt, Marc
, p. 9649 - 9650 (1998)
The use of a homopolymer 2a of methyl 5-vinylsalicylate, as well as of statistical copolymers 2b-f, in the diastereoselective protonation of the chiral keto-enolate 1 leads to selectivities of up to 93:7 in favor of product 3.
C3 and C6 Modification-Specific OYE Biotransformations of Synthetic Carvones and Sequential BVMO Chemoenzymatic Synthesis of Chiral Caprolactones
Issa, Issa S.,Toogood, Helen S.,Johannissen, Linus O.,Raftery, James,Scrutton, Nigel S.,Gardiner, John M.
supporting information, p. 2983 - 2988 (2019/01/24)
The scope for biocatalytic modification of non-native carvone derivatives for speciality intermediates has hitherto been limited. Additionally, caprolactones are important feedstocks with diverse applications in the polymer industry and new non-native terpenone-derived biocatalytic caprolactone syntheses are thus of potential value for industrial biocatalytic materials applications. Biocatalytic reduction of synthetic analogues of R-(?)-carvone with additional substituents at C3 or C6, or both C3 and C6, using three types of OYEs (OYE2, PETNR and OYE3) shows significant impact of both regio-substitution and the substrate diastereomer. Bioreduction of (?)-carvone derivatives substituted with a Me and/or OH group at C6 is highly dependent on the diastereomer of the substrate. Derivatives bearing C6 substituents larger than methyl moieties are not substrates. Computer docking studies of PETNR with both (6S)-Me and (6R)-Me substituted (?)-carvone provides a model consistent with the outcomes of bioconversion. The products of bioreduction were efficiently biotransformed by the Baeyer–Villiger monooxygenase (BVase) CHMO_Phi1 to afford novel trisubstituted lactones with complete regioselectivity to provide a new biocatalytic entry to these chiral caprolactones. This provides both new non-native polymerization feedstock chemicals, but also with enhanced efficiency and selectivity over native (+)-dihydrocarvone Baeyer–Villigerase expansion. Optimum enzymatic reactions were scaled up to 60–100 mg, demonstrating the utility for preparative biocatalytic synthesis of both new synthetic scaffold-modified dihydrocarvones and efficient biocatalytic entry to new chiral caprolactones, which are potential single-isomer chiral polymer feedstocks.
Some novel electron transfer mediated cascade ring-opening reactions of bicyclo[4.1.0]ketones
Batey, Robert A.,Harling, John D.,Motherwell, William B.
, p. 11421 - 11444 (2007/10/03)
The radical ring-opening reactions of cyclopropyl ketones, mediated by samarium (II) iodide and other electron transfer agents are described. This strategy allows tandem rearrangement cyclisation reactions and the trapping of the resultant samarium (III) enolates by a variety of electrophiles, for the construction of complex bicyclic systems.
SAMARIUM(II) IODIDE PROMOTED RADICAL RING OPENING REACTIONS OF CYCLOPROPYL KETONES
Batey, Robert A.,Motherwell, William B.
, p. 6649 - 6652 (2007/10/02)
Radical ring opening reactions of cyclopropyl ketones mediated by samarium(II) iodide-induced single electron transfer have permitted the elaboration of a tandem rearrangement cyclisation strategy.The resultant samarium enolates may be effectively quenched on oxygen or carbon by electrophiles.Key Words: Samarium(II) Iodide Reduction; Cyclopropylcarbinyl Radical Rearrangement; Cyclopropyl Ketone; Radical Cyclisation; Samarium Enolate.
Samarium(II) iodide promoted radical ring opening reactions of cyclopropyl ketones
Batey,Motherwell
, p. 6211 - 6214 (2007/10/02)
Radical ring opening reactions of cyclopropyl ketones mediated by samarium(II) iodide-induced single electron transfer have permitted the elaboration of a tandem rearrangement cyclisation strategy. The resultant samarium enolates may be effectively quenched on oxygen or carbon by electrophiles.
Amphiphilic Reactions by Means of Exceptionally Bulky Organoaluminum Reagents. Rational Approach for Obtaining Unusual Equatorial, Anti-Cram, and 1,4 Selectivity in Carbonyl Alkylation
Maruoka, Keiji,Itoh, Takayuki,Sakurai, Minoru,Nonoshita, Katsumasa,Yamamoto, Hisashi
, p. 3588 - 3597 (2007/10/02)
Exceptionally bulky, oxygenophilic organoaluminum reagents, methylaluminum bis(2,6-di-tert-4-alkylphenoxide) (MAD and MAT), have been successfully utilized for stereoselective activation of carbonyl moiety.Combination of MAD or MAT with carbon nucleophiles such as organolithiums or Grignard reagents generates a new amphiphilic reaction system in which the alkylation may be interpreted as the nucleophilic addition of a reactive organometallic compound to an electrophilically activated carbonyl substrate in order to account for the regio- and stereochemical consequences.In contrast to the ordinary alkylations, the amphilic alkylation disclosed herein would be categorized into the new, yet unexplored class of alkylation that exhibits high chemoselectivity to carbonyl compounds, and more significantly it allows excellent equatorial and anti-Cram selectivity in carbonyl alkylations, hitherto difficult by the existing methodologies.Further, unusual conjugate addition of organolithium reagents to α,β-unsaturated carbonyl compounds has been accomplished by using the amphiphilic reaction system.
UNUSUAL CONJUGATE ADDITION OF ORGANOLITHIUM REAGENT TO α,β-UNSATURATED KETONE
Maruoka, Keiji,Nonoshita, Katsumasa,Yamamoto, Hisashi
, p. 5723 - 5726 (2007/10/02)
The conjugate addition of organolithium reagent to α,β-unsaturated ketone has been accomplished with methylaluminum bis(2,6-di-tert-butyl-4-alkylphenoxide) (MAD and MAT).Here combination of alkyllithium and MAD (or MAT) constitutes an amphiphilic system that allows to exhibit unusual selectivity in the alkylation of enones with alkyllithium.
