Regioselective C5-alkylation and C5-methylcarbamate formation of 2,3-dihydro-4-pyridones and C3-alkylation and C3-methylcarbamate formation of 4-(pyrrolidin-1-yl)furan-2(5H)-one

Gu, Xingxian; Georg, Gunda I.

doi:10.1016/j.tetlet.2015.09.004

Cited by 7 publications

(1 citation statement)

References 19 publications

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“…Maculalactone A, a tribenzyl butenolide compound isolated from the marine cyanobacterium Kyrtuthrix maculans , was found to possess intriguing bioactivity, which inhibited the growth of marine bivalves on rock surfaces . Our synthesis commenced with the alkylation of lactone 2 b by using benzaldehyde and triethylsilane under acidic conditions, resulting in a desirable α‐benzyl lactone 3 in 92 % yield . Hydrolysis of 3 with aqueous HCl (86 %), followed by triflation produced triflate 4 in 72 % yield completing a highly efficient formal synthesis of maculalactone A.…”

Section: Methodsmentioning

confidence: 99%

Tandem [1,2]‐Wittig Rearrangement/Lactonization of γ‐Benzyloxy Vinylogous Urethanes: Application to the Synthetic Studies of Maculalactone A, Planchol C and γ‐Lycorane

2017

Asian J Org Chem

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At andem [1,2]-Wittig rearrangement/lactonization of g-benzyloxy vinylogousu rethanes is presented herein. The resulting butenolides featuring various benzyl substituents at the g-position are structurally diverse compounds found in natural products. The usefulness of this synthetic approach was demonstrated in the formal synthesis of maculalactone A, rapid assemblyo ft he tricyclic core of planchol C, and the total synthesis of g-lycorane.The rearrangemento fa-alkoxyc arbanions is one of the important reaction for CÀCb ondf orming methods. In particular,t he [2,3]-Wittig rearrangement,w hich allow the transformationo f an allylic ether into ah omoallylic alcohol, has been highly developedi nv arious fields of organic synthesis.[1] By contrast, the [1,2]-Wittig rearrangement has received less attention [2] and has rarely been applied in the synthesis of naturalp roducts [3] and pharmaceuticals.[2s] This lack of popularity has mainly resulted from the preparation of a-etherealc arbanions, which relies heavily on the use of the benzyl group as ac arbanionstabilizing group in the anion formation step (Scheme 1a). However,t he stability and synthetic potentialo ft he phenyl ring limits the synthetic applications of this approach. [1,2]-shifts of electron-withdrawing group (EWG)-bearing ethers involvingt he formation of new stereocenters are scarce, because EWGs stabilizing the a-ethereal carbanions can sometimesu ndergo eliminationr eactions to form carbonyl compounds (Scheme 1b).[4] To date, only af ew examples have been reported that allow accesst ot he corresponding carbinols in the presenceo fE WGs, such as ketones, [5] acetamides, [6] and b-lactams (Scheme 1c).[7] Recently,s ignificant progress has been made using an asymmetric tandem [1,2]-Wittig/Aldol or [1,2]-Wittig/Mannich reactions of glycolate esters, which provide a,b-dihydroxy esters and a-hydroxy b-amino esters in high stereoselectivities, respectively. [3b, 8] These tandem approaches not only strikingly complement traditional carbanion-stabilizing groups but also allow ac ascade sequence to efficiently forge complex chemical structures.Inspired by our previouss tudies on the asymmetric aldol reaction of g-benzyloxy vinylogousu rethanew ith aldehydes, under certain circumstances, aminute amount of g-benzyl substitutedv inylogous urethane lactone was obtained (Scheme 2a). [9] We envisioned that the rearrangement of av inylogous urethane system possessing an EWG-bearing moiety and ab enzyloxy-migrating terminus might undergo at andem [a] Dr

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Section: Methodsmentioning

confidence: 99%

Tandem [1,2]‐Wittig Rearrangement/Lactonization of γ‐Benzyloxy Vinylogous Urethanes: Application to the Synthetic Studies of Maculalactone A, Planchol C and γ‐Lycorane

2017

Asian J Org Chem

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ChemInform Abstract: Regioselective C5‐Alkylation and C5‐Methylcarbamate Formation of 2,3‐Dihydro‐4‐pyridones and C3‐Alkylation and C3‐Methylcarbamate Formation of 4‐(Pyrrolidin‐1‐yl)furan‐2(5H)‐one.

Georg

2016

ChemInform

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Bicyclic 6-6 Systems With One Bridgehead (Ring Junction) Nitrogen Atom: No Extra Heteroatom

Бардасов¹,

Ievlev²

2022

Comprehensive Heterocyclic Chemistry IV

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Regioselective C5-alkylation and C5-methylcarbamate formation of 2,3-dihydro-4-pyridones and C3-alkylation and C3-methylcarbamate formation of 4-(pyrrolidin-1-yl)furan-2(5H)-one

Cited by 7 publications

References 19 publications

Tandem [1,2]‐Wittig Rearrangement/Lactonization of γ‐Benzyloxy Vinylogous Urethanes: Application to the Synthetic Studies of Maculalactone A, Planchol C and γ‐Lycorane

Tandem [1,2]‐Wittig Rearrangement/Lactonization of γ‐Benzyloxy Vinylogous Urethanes: Application to the Synthetic Studies of Maculalactone A, Planchol C and γ‐Lycorane

ChemInform Abstract: Regioselective C5‐Alkylation and C5‐Methylcarbamate Formation of 2,3‐Dihydro‐4‐pyridones and C3‐Alkylation and C3‐Methylcarbamate Formation of 4‐(Pyrrolidin‐1‐yl)furan‐2(5H)‐one.

Bicyclic 6-6 Systems With One Bridgehead (Ring Junction) Nitrogen Atom: No Extra Heteroatom

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