26620-41-7Relevant academic research and scientific papers
Ester Groups as Effective Ligands in Chelate-Controlled Additions of Cuprates and Grignard Reagents to Chiral β-Formyl Esters
Reissig, Hans-Ulrich,Angert, Hubert,Kunz, Thomas,Janowitz, Agnes,Handke, Gabriele,Bruce-Adjei, Emanuel
, p. 6280 - 6285 (1993)
Addition of cuprates to chiral methyl β-formyl carboxylates 1a-1d provided γ-lactones 2-7 in excellent trans-selectivity.The high diastereofacial selectivity was only obtained employing diethyl ether as solvent while tetrahydrofuran gave inferior results.Similar solvent effects were observed in the additions of various Grignard reagents to 1a, which afforded γ-lactones 2, 3, 12, and 13 in moderate trans-selectivity.The best solvent for these reactions was dichloromethane.The 1,3-induction of cuprate additions was studied by using aldehydes 8a-8c.The results obtained were interpreted in terms of chelate-controlled additions with formation of seven-membered ring chelates which involve both carbonyl functions of aldehyde 1 or 8.The function of ester groups as effective ligands of lithium or MgX cations may also be of importance for other stereoselective reactions employing organometallic reagents.
MnO2-promoted carboesterification of alkenes with anhydrides: A facile approach to γ-lactones
Wu, Lihuan,Zhang, Zhenming,Liao, Jianhua,Li, Jianxiao,Wu, Wanqing,Jiang, Huanfeng
supporting information, p. 2628 - 2631 (2016/02/18)
An efficient carboesterification of alkenes with anhydrides promoted by MnO2 has been developed to afford functionalized γ-lactones in good to excellent yields. This method shows a broad substrate scope and provides a valuable and convenient synthetic tool for constructing γ-lactones.
Regio- and stereoselective nickel-catalyzed homoallylation of aldehydes with 1,3-dienes
Kimura, Masanari,Ezoe, Akihiro,Mori, Masahiko,Iwata, Keisuke,Tamaru, Yoshinao
, p. 8559 - 8568 (2007/10/03)
Ni(acac)2 catalyzes homoallylation of aldehydes with 1,3-dienes in the presence of triethylborane. Triethylborane serves as a reducing agent delivering a formal hydride to the C2 position of 1,3-dienes, thus generating a formal homoallyl anion species and enabling the novel homoallylation of aldehydes. The reaction proceeds smoothly at room temperature in the absence of any phosphane or nitrogen ligands and is highly regioselective and stereoselective for a wide variety combination of aldehydes and 1,3-dienes: e.g., isoprene and benzaldehyde combine to give a mixture of anti- and syn-1-phenyl-3-methyl-4-penten-1-ol (2.2) in a ratio of 15:1 in 90% yield. Under the conditions, sterically congested aliphatic aldehydes and ketones show low yields. In such cases, diethylzinc serves as a substitute for triethylborane and yields the expected products in good yields with similarly high regio- and stereoselectivity. 1,3-Cyclohexadiene is one exception among 24 kinds of dienes examined and undergoes allylation (not homoallylation) selectively.
Solid-support synthesis of 1,2-diols and γ-lactones through addition of α-(benzoyloxy)crotylindium reagents to aldehydes
Cossy, Janine,Rasamison, Chrystelle,Pardo, Domingo Gomez,Marshall, James A.
, p. 629 - 633 (2007/10/03)
A procedure for the solid phase synthesis of 1,2-diols and γ-lactones from α-(hydroxy)crotylstannane has been developed through transmetalation with InBr3. A variety of 1,2-diols and γ-lactones were synthesized in satisfactory yields and, in some cases, with excellent diastereoselectivity. The products are formed free of tin contamination.
Highly diastereoselective reduction of γ-keto amides: Diastereoselective synthesis of γ-butyrolactones with contiguous chiral centers
Satoh, Masami,Washida, Sakurako,Takeuchi, Sawako,Asaoka, Morio
, p. 227 - 236 (2007/10/03)
Diastereoselective reduction of γ-keto amides, which were easily prepared by the reaction of a zinc homoenolate of butanamide with acid chlorides in the presence of Pd(0) catalyst, was achieved. Cyclization of the products, γ-hydroxy amides, under various
Substrate-directed diastereoselective hydroformylations, 1: Substrate-directed diastereoselective hydroformylation of methallylic alcohols - Development of an efficient catalyst-directing group for rhodium-catalyzed hydroformylation
Breit, Bernhard
, p. 1841 - 1851 (2007/10/03)
The development of an efficient catalyst-directing group based on ortho-diphenylphosphanyl benzoate (o-DPPB) for the substrate-directed, diastereoselective hydroformylation of methallylic alcohols 5 is described. The hydroformylation of methallylic o-DPPB esters 9 provides the corresponding syn-aldehydes 10 with diastereoselectivities of up to 96:4. A specific steric demand of the substituent at the stereogenic center of the methallylic derivatives 9 was found to be necessary to achieve a high degree of stereoselectivity. Experiments have been performed that prove that the o-DPPB group acts as a catalyst-directing group by reversibly coordinating to the catalyst. The removal of the o-DPPB group was accomplished by means of alkaline hydrolysis, thereby furnishing the lactols 6. Oxidation of 6 provides the corresponding γ-lactones 7. VCH Verlagsgesellschaft mbH, 1997.
A novel stereoselective route to γ-butyrolactones
Casey,Manage,Murphy
, p. 965 - 968 (2007/10/02)
Treatment of the products obtained from conjugate additions of sulfoxides to α,β-unsaturated carbonyl compounds with soft electrophiles resulted in intramolecular displacement of the sulfinyl group by the carbonyl to give γ-butyrolactones. This novel cyclisation works best for benzylic sulfoxides and provides a concise route to trans-β,γ-disubstituted lactones with high stereoselectivity.
A stereochemical study on the intramolecular hydrosilylation of α,β-unsaturated esters
Denmark, Scott E.,Forbes, David C.
, p. 5037 - 5040 (2007/10/02)
The intramolecular hydrosilylation of several 3-methyl-4-siloxy-2-butenoates afforded cis disubstituted lactones after desilylation. The diastereoinduction was sensitive to the bulk of the allylic substituent, but not to the groups on silicon. The origin
Stereoselective Reduction of γ-Oxobutanoic Acids Using DIBAL-H and ZnCl2
Frenette, R.,Monette, M.,Bernstein, M. A.,Young, R. N.,Verhoeven, T. R.
, p. 3083 - 3089 (2007/10/02)
A variety of γ-aromatic γ-ketobutanoic acids can be reduced selectively, under optimized conditions, by the use of DIBAL-H and ZnCl2 to provide the (RS,SR)-γ-aryl-γ-hydroxy-β-methylbutanoic acids.Further evidence has been gathered to support the hypothesis that the reaction proceeds by formation of a seven-membered ring complex with the aluminium or zinc atom bridging the ketone and carboxyl groups which preceeds the reduction step and that this templated reduction accounts for observed high diastereoselectivity.Also we have shown that some γ-aryl-γ-butyrolactones can be easily transformed via an oxidative cleavage of the aromatic ring to provide selective synthesis of either cis- or trans-tetrahydro-3-methyl-5-oxo-2-furancarboxylic acid derivatives.
