Reaction of unsaturated sulfoxides with alkyllithiums

Neef, Günter; Eder, Ulrich; Seeger, A.

doi:10.1016/s0040-4039(00)77734-3

Cited by 30 publications

(7 citation statements)

References 9 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Okamura and co-workers metalated diastereomeric allenes ( 49 and its isomer) and found that deuteration gave identical products . However, treatment of sulfoxide 48 and its isomer with MeLi to give 49 , a reaction that probably goes through an allenyllithium intermediate, proceeded stereospecifically with retention of configuration, implying some stereochemical lifetime of the lithium reagent before protonation occurs …”

Section: Discussionmentioning

confidence: 99%

Solution Structure and Stereochemistry of Alkyl- and Silyl-Substituted Allenyl-Propargyllithium Reagents

et al. 1999

View full text Add to dashboard Cite

Analysis of 13 C chemical shifts and Li-C couplings showed that allenyllithium (5A-Li) was a mixture of monomer and dimer in THF, both with an allenyl structure. Similarly, the metalation products of 2-butyne (6A-Li), 4-methylpentyne (9A-Li), and 4,4-dimethylpentyne (21A-Li) in THF, as well as several 1, 3-dialkyl (32A-Li, 33A-Li, 34A-Li) propargyl-allenyllithiums formed by metalation or Li/Sn exchange were all monomeric lithioallenes in THF. Compound 6A-Li was shown to have less than 5% and 21A-Li less than 3% of the propargyllithium isomers (6P-Li, 21P-Li) present from analysis of residual broadening of the propargyl carbon by Li-C coupling. The reagent prepared by metalation of dicyclopropylacetylene (8P-Li) has a propargyl structure, but two related reagents with a cyclobutane spanning the 3,3-positions (37A-Li and 39A-Li) had allenyl structures. Several triorganosilyl-substituted reagents were also investigated. Those with silyl groups at the allenyl position (28A-Li, 31A-Li) are allenyllithiums, those with silyl groups at the propargyl position (22-Li to 26P-Li) showed chemical shifts intermediate between those of allenyl and propargyl isomers, and the shifts were strongly temperature-dependent under some conditions. These compounds are probably equilibrating mixtures of allenyl and propargyllithiums or equilibrating mixtures of unsymmetrically π-complexed structures, with barriers to interconversion (∆G q -150 ) below 4 kcal/mol. Several of the organolithium reagents studied had diastereotopic carbon signals (SiMe 2 , CMe 2 , or CPh 2 groups), which allowed determination of barriers to configurational inversion of the chiral allenyl fragment. Barriers from 6.1 kcal/mol (26A-Li in dimethyl ether) to 14.5 kcal/mol (39A-Li in 3:2 THF/ether) were measured.

show abstract

Section: Discussionmentioning

confidence: 99%

Solution Structure and Stereochemistry of Alkyl- and Silyl-Substituted Allenyl-Propargyllithium Reagents

et al. 1999

View full text Add to dashboard Cite

show abstract

“…The α-benzenesulfanyl enol ethers depicted in Scheme 6 were oxidised to the corresponding sulfoxides using MCPBA and NaHCO 3 (60-94% yield). Sulfoxides 20, 26, 29 and 35, underwent sulfoxide-lithium exchange [26][27][28] on treatment with n-BuLi in THF at -78°C for 30 min to give the α-lithiated enol ethers. 29 Quenching the reaction mixture with methanol at -78°C returned the enol ethers 48-50 and 51 in quantitative yield (Scheme 7).…”

Section: Methodsmentioning

confidence: 99%

A Synthesis of α-Lithiated Enol Ethers from α-Arenesulfinyl Enol Ethers: Ni(0)- and Pd(0)-Catalysed Coupling of Enol Triflates and Phosphates Derived from Lactones with Sodium Arenethiolates Gives α-Arenesulfanyl Enol Ethers

Milne¹,

Kocieński²

2003

Synthesis

View full text Add to dashboard Cite

A three-step synthesis of stable and storable α-benzenesulfinyl enol ethers from lactones entails (a) conversion of a lactone to an enol triflate or phosphate; (b) Ni(0) and Pd(0) cross-coupling of the enol triflate or phosphate with a sodium arenethiolate to give an α-arenethio enol ether; and (c) oxidation of an arenethio group to a sulfoxide. The α-benzenesulfinyl enol ethers undergo sulfoxidelithium exchange on reaction with n-BuLi to give α-lithiated enol ethers thus making the α-benzenesulfinyl group a surrogate for the trialkylstannyl group which has hitherto served as the most common precursor to α-lithiated enol ethers.

show abstract

“…[2,3]-Sigmatropic rearrangements involving propargylic sulfenates have been used in synthetic approaches to natural products such as prostacyclins, 305 steroids, 306 and retinoids, 307 among others. Within the context of the synthesis of steroids, mestranol has been employed as a starting material to provide a mixture of two diastereomeric allenyl sulfoxides 509 through sulfenate−sulfoxide rearrangement promoted by sulfenylation with PhSCl (Scheme 87).…”

Section: [23]-sigmatropic Rearrangement From Propargylic Sulfenatesmentioning

confidence: 99%

From Allylic Sulfoxides to Allylic Sulfenates: Fifty Years of a Never-Ending [2,3]-Sigmatropic Rearrangement

et al. 2017

View full text Add to dashboard Cite

The [2,3]-sigmatropic rearrangement of allylic sulfoxides to allylic sulfenates is a reversible process, generally shifted toward the sulfoxide. In the presence of thiophiles, the sulfenate is trapped, and allylic alcohols are obtained under mild conditions. In most cases, a good transfer of stereochemical information through an ordered transition state is obtained. Furthermore, the ease of coupling this process with other versatile, stereocontrolled reactions has enhanced the usefulness of this protocol. This review aims to provide a comprehensive survey of this rearrangement and its application in the synthesis of natural and bioactive products.

show abstract

Reaction of unsaturated sulfoxides with alkyllithiums

Cited by 30 publications

References 9 publications

Solution Structure and Stereochemistry of Alkyl- and Silyl-Substituted Allenyl-Propargyllithium Reagents

Solution Structure and Stereochemistry of Alkyl- and Silyl-Substituted Allenyl-Propargyllithium Reagents

A Synthesis of α-Lithiated Enol Ethers from α-Arenesulfinyl Enol Ethers: Ni(0)- and Pd(0)-Catalysed Coupling of Enol Triflates and Phosphates Derived from Lactones with Sodium Arenethiolates Gives α-Arenesulfanyl Enol Ethers

From Allylic Sulfoxides to Allylic Sulfenates: Fifty Years of a Never-Ending [2,3]-Sigmatropic Rearrangement

Contact Info

Product

Resources

About