101451-40-5Relevant academic research and scientific papers
Iodine(III)-Mediated Contraction of 3,4-Dihydropyranones: Access to Polysubstituted γ-Butyrolactones
Dagenais, Robin,Lussier, Tommy,Legault, Claude Y.
supporting information, p. 5290 - 5294 (2019/09/03)
Functionalized γ-butyrolactones are privileged structures in the field of medicinal chemistry; they are found in numerous natural products and synthetic compounds with diverse biological activities. The oxidative ring contraction of 3,4-dihydropyran-2-one derivatives represents a promising yet underappreciated strategy to access these compounds. To the best of our knowledge, very few examples of this strategy have been reported, with limited investigation of the influence of stereogenic centers on the starting dihydropyranones. We investigated the iodine(III)-mediated contraction of a representative set of dihydropyranone derivatives. The method gives rapid access to functionalized γ-butyrolactones in good yields. The reaction scope was investigated, and the method was found to support various levels of substituents, even enabling access to sterically congested quaternary centers. The stereoselectivity was investigated using chiral substrates and a chiral iodine(III) reagent.
Lactone Synthesis by Enantioselective Orthogonal Tandem Catalysis
Mishra, Sourabh,Aponick, Aaron
supporting information, p. 9485 - 9490 (2019/08/06)
In this work, we report enantioselective orthogonal tandem catalysis for the one pot conversion of Meldrum's acid derivatives and alkynes into δ-lactones. This new transformation, which resembles a formal [4+2] cycloaddition with concomitant decarboxylation and loss of acetone, proceeds in high yields and excellent enantioselectivity (up to 99 % ee) over a broad substrate scope. The products are densely functionalized and ripe for further transformations, as demonstrated here by both ring-opening reactions and reduction to saturated lactones. It was discovered that a new and serendipitously formed AgI-Me-StackPhos complex efficiently catalyzes the highly selective 6-endo-dig cyclization, completely reversing the regiochemistry that has been previously reported in related systems. More generally, in this study we identify a pair of compatible catalysts for alkyne difunctionalization that operate concurrently, which enable the alkyne to act as both a nucleophile and an electrophile in sequential one-pot transformations.
A new approach to 4,6-disubstituted-3,4-dihydropyran-2-ones by Domino Michael addition-cyclization reaction under PTC conditions
Gaggero, Nicoletta,Albanese, Domenico C.M.,Nava, Donatella
, p. 8744 - 8749 (2015/01/08)
Domino Michael addition-cyclization reactions of α,β-unsaturated carbonyl compounds with activated 1,3-dithiane-2-carbothioate esters under solid-liquid phase transfer catalysis conditions provide 4,6-disubstituted-3,4-dihydropyran-2-one-3,3-dithioacetals
Asymmetric access to the smallest enolate intermediate via organocatalytic activation of acetic ester
Chen, Shaojin,Hao, Lin,Zhang, Yuexia,Tiwari, Bhoopendra,Chi, Yonggui Robin
supporting information, p. 5822 - 5825 (2013/12/04)
An NHC-catalyzed activation of acetic esters to afford enolate intermediates is disclosed. The catalytically generated triazolium enolate intermediates serve as two-carbon nucleophiles that undergo highly enantioselective reactions with enones and α,β-uns
Enantioselective Mukaiyama-Michael with 2-enoyl pyridine N-oxides catalyzed by PYBOX-DIPH-Zn(ii)-complexes at ambient temperature
Rout, Subhrajit,Ray, Sumit K.,Singh, Vinod K.
, p. 4537 - 4545 (2013/08/23)
A chiral PYBOX-DIPH-Zn(ii) catalyzed enantioselective Mukaiyama-Michael reaction of acyclic silyl enol ethers with 2-enoylpyridine N-oxides has been studied in external additive free conditions at ambient temperature. The methodology offers straightforward access to a variety of functionalized chiral 1,5-dicarbonyl compounds, which could easily be elaborated into synthetically viable pyrones via hydrolysis followed by cyclization. A transition state model has been proposed to explain the stereochemical outcome. The Royal Society of Chemistry 2013.
N-heterocyclic carbene-catalyzed generation of α,β-unsaturated acyl imidazoliums: Synthesis of dihydropyranones by their reaction with enolates
Ryan, Sarah J.,Candish, Lisa,Lupton, David W.
supporting information; experimental part, p. 14176 - 14177 (2010/02/16)
(Chemical Equation Presented) Catalytic generation of α,β- unsaturated acyl imidazolium cations and enolates has been achieved, and their involvement in a Michael addition acylation sequence exploited, to provide a range of dihydropyranones. α,β-Unsaturat
N-Heterocyclic carbene catalyzed ring expansion of formylcyclopropanes: Synthesis of 3,4-dihydro-α-pyrone derivatives
Li,Dai,You
supporting information; experimental part, p. 1623 - 1625 (2009/09/06)
N-Heterocyclic carbene catalyzed ring expansion of readily accessible 2-acyl-1-formylcyclopropanes was developed. With 5 mol % of triazolium salt 5 and 30 mol % of DBU, ring expansion of various 2-acyl-1-formylcyclopropanes led to 3,4-dihydro-α-pyrones in
Facile synthesis of 3,4-dihydro-α-pyrones via Michael reaction-O-acylation sequences
Kobayashi, Shu,Moriwaki, Mitsuhiro
, p. 551 - 552 (2007/10/03)
3,4-Dihydro-α-pyrones were prepared in excellent yields with high stereoselectivities by the trityl salt-catalyzed Michael reaction and sequential intramolecular O-acylation of the intermediary silyl enol ethers using a mercury (II) salt (one-pot reaction
