Methoxy(phenylthio)(trimethylsilyl)methane as a one-carbon homologation reagent: efficient 1,4-addition of a formyl or a carboxy anion equivalent to cyclic .alpha.-enones concomitant with in situ .alpha.-alkylation

Otera, Junzo; Niibo, Y.; Nozaki, Hitosi

doi:10.1021/jo00282a010

Cited by 27 publications

(5 citation statements)

References 2 publications

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“…821 R-Silyl enolates have often been used in Michael reactions, with the silyl group contributing to the selectivity for conjugate addition over direct attack on the carbonyl group, 822 and sometimes perhaps providing extra bulk to affect the stereochemistry of attack on the resultant enolate. 823 It is not usually possible to identify any stereochemical consequences, but the sheer size of the nucleophile in the reaction 1572 f 1573 may well be contributing to the high enantiomeric excess found in this reaction, which was part of a synthesis of methyl jasmonate (Scheme 383). 824 A special example of an R-silyl ketone is (trimethylsilyl)ketene 1574, which undergoes cycloaddition to aldehydes in the presence of Lewis acids to give β-lactones 1575.…”

Section: R-silyl Carbonyl Compoundsmentioning

confidence: 99%

Stereochemical Control in Organic Synthesis Using Silicon-Containing Compounds

1997

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Section: R-silyl Carbonyl Compoundsmentioning

confidence: 99%

Stereochemical Control in Organic Synthesis Using Silicon-Containing Compounds

1997

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“…Other arylthiomethyl methyl ethers ( 1a,c − f ) were prepared by the treatment of the corresponding arylthiols with chloromethyl methyl ether under basic conditions (Scheme ). Deprotonation of thus obtained arylthiomethyl methyl ethers with butyllithium followed by the reaction with alkyl iodides gave the corresponding α-arylthioalkyl methyl ethers ( 2 ) . The reaction of the anion of 1 with aldehydes also proceeded smoothly to give β-hydroxy-α-arylthioalkyl methyl ethers ( 3 ) (Scheme ) .…”

Section: Resultsmentioning

confidence: 99%

Electrooxidative Inter- and Intramolecular Carbon−Carbon Bond Formation Using Organothio Groups as Electroauxiliaries

et al. 1998

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The introduction of an organothio group to an alpha-carbon of ethers results in significant decrease of the oxidation potentials. Anodic oxidation of alpha-organothioethers gives rise to facile cleavage of the C-S bond and the introduction of carbon nucleophiles on the carbon. Allylsilanes, silyl enol ethers, and trimethylsilyl cyanide serve as effective carbon nucleophiles. The anodic oxidation of the alpha-organothioethers having a carbon-carbon double bond in an appropriate position using Bu(4)NBF(4) as the supporting electrolyte leads to the effective cyclization and the introduction of the fluoride to one of the formal olefinic carbon. The present study demonstrates the effectiveness of organothio groups as electroauxiliaries in electrooxidative inter- and intramolecular carbon-carbon bond formation.

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“…Several acyclic derivatives have been shown to react as masked formyl and acyl anion synthons. Some selected examples are a-silyl sulfides (PhSCH 2 TMS 2 and MeO(PhS) CHTMS 3 ), a-lithiated derivatives such as tris(phenylthio) methyllithium 4 and methoxy(phenyldimethylsilyl)methyllithium, 5 and a-metalated enol carbamates. 6 Formaldehyde hydrazones have been used as neutral formyl anion equivalents in Michael additions to conjugated enones, 7 while protected hydroxymalonitriles were reported for the preparation of activated esters in the synthesis of dipeptides.…”

Section: Introductionmentioning

confidence: 99%

Synthesis and stereoselective functionalization of silylated heterocycles as a new class of formyl anion equivalents

Degl’Innocenti¹,

Pollicino²,

Capperucci³

2006

Chem. Commun.

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The fluoride ion-induced reactivity of a series of silyl heterocycles leads to the generation of nucleophilic species capable of interacting with electrophiles, thus disclosing new classes of formyl and acyl anion synthons. Moreover, when reacting stereodefined molecules, the stereoinformation of the reacting carbon-silicon bond is transferred to the newly formed carbon-carbon bond, suggesting possible applications in stereoselective synthesis. Thus, silyl dithiolanes, oxathiolanes, dioxolanes, thiazolidines and oxazolidines can be efficiently and stereoselectively functionalized under fluoride ion conditions in the presence of electrophiles. While direct access to silyl heterocycles is generally either prevented or troublesome, a novel protocol for their synthesis has also been developed, together with a simple general access route to several functionalized and stereodefined mercaptans, building blocks for the construction of silyl heterocycles.

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Methoxy(phenylthio)(trimethylsilyl)methane as a one-carbon homologation reagent: efficient 1,4-addition of a formyl or a carboxy anion equivalent to cyclic .alpha.-enones concomitant with in situ .alpha.-alkylation

Cited by 27 publications

References 2 publications

Stereochemical Control in Organic Synthesis Using Silicon-Containing Compounds

Stereochemical Control in Organic Synthesis Using Silicon-Containing Compounds

Electrooxidative Inter- and Intramolecular Carbon−Carbon Bond Formation Using Organothio Groups as Electroauxiliaries

Synthesis and stereoselective functionalization of silylated heterocycles as a new class of formyl anion equivalents

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