Cleavage of vinyl carbon-silicon bond with tetrabutylammonium fluoride

Oda, Hiroji; Sato, Mitsuyoshi; Morizawa, Yoshitomi; Oshima, Koichiro; Nozaki, Hitosi

doi:10.1016/s0040-4020(01)96677-3

Cited by 69 publications

(27 citation statements)

References 30 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…[52] It is well known that F -adds to the silicon atom creating pentacovalent species that can easily move away from the molecule. Hence, our first attempts of removal of the silyl moiety from the β-silylalkenals [13] were performed with fluoride carriers such as KF, BF 3 , TBAF and the obtained results are reported in Table 12.…”

Section: Fluoride-promoted Transformation Of Silylformylation Productsmentioning

confidence: 99%

Synthesis and Reactivity of Silylformylation Products Derived from Alkynes

2008

View full text Add to dashboard Cite

The silylformylation reaction of unsaturated compounds consists of the rhodium-catalysed addition of a R 3 Si and a CHO moiety to a carbon-carbon multiple bond. The silylformylation process is applicable to both terminal and internal alkynes and is tolerant towards several functional groups. Many factors can influence the chemoselectivity of the reaction that generally affords β-silylalkenals with high yields and regioselectivity. The β-silylalkenals are polyfunctionalised substrates that can be submitted to several chemical transformations and in particular can undergo fluoride-promoted (TBAF) aryl migration from an aryldimethylsilyl group to the adjacent carbon atom thus generating 2-(arylmethyl)-aldehydes, important industrial precursors of perfumes. This silylformylation-aryl migration two-steps sequence can be applied to functionalised alkyne precursors and chemo-, regio-and stereoselectivity of the products can be modulated according to the nature and the position of the functional

show abstract

Section: Fluoride-promoted Transformation Of Silylformylation Productsmentioning

confidence: 99%

Synthesis and Reactivity of Silylformylation Products Derived from Alkynes

2008

View full text Add to dashboard Cite

show abstract

“…1e These reactions are often carried out under very mild conditions in excellent yields. 2 This method has been applied to the synthesis of terminal conjugated trienes (eqs 8 and 9). 10, 13 2-(Trimethylsilyl)ethoxymethyl groups can also be effectively removed from various substrates (eq 2).…”

Section: Original Commentarymentioning

confidence: 99%

Tetra-n-butylammonium Fluoride

Li¹,

Sun²,

DiMagno³

2007

Encyclopedia of Reagents for Organic Synthesis

View full text Add to dashboard Cite

“…Since NMR studies, including NOE experiments, on the cyclisation products proved inconclusive, we chose to remove the tether and investigate the ring-opened protodesilylated product. Reaction of 5a with KF in a MeOH-THF solvent mix at 60°C effected clean protodesilylation 22 and the formation of two diol products 12 and 13, with the allene 13 resulting from ipso protodesilylation accounting for the major product (Scheme 5). Exposure of this diol mixture to acetone in the presence of PTSA and Na 2 SO 4 provided the corresponding acetonides 14 and 15.…”

Section: Scheme 4 Brønsted Acid Mediated Cyclisation Provides An Alcomentioning

confidence: 99%

Using a Temporary Silicon Connection in a Highly Stereoselective Synthesis of a New Class of Cyclic Allenylsilanes

Ramalho¹,

Beignet²,

Humphries³

et al. 2005

Synthesis

View full text Add to dashboard Cite

Aldehyde 4 reacts in the presence of TMSOTf and an acid scavenger to provide the corresponding oxasilacycle 5 in very good yield and as a single diastereoisomer. The sense of 1,3-stereoinduction serves to introduce a 1,3-syn-diol relationship into the cyclic product. This is in accord with a previous study involving an analogous intramolecular allylation.Forming a tether between two reacting partners allows a subsequent reaction to proceed in an intramolecular fashion and benefit from the advantages associated with unimolecular processes. However, if the tether is then cleaved, the product obtained is the result of a net intermolecular reaction. 2 We recently employed such a strategy in the stereoselective allylation of a series of aldehydes 1, in which the carbinol centre provided the site for appending an allylsilane through its g-terminus (Scheme 1). 3 Aldehyde 1 reacted in the presence of TMSOTf and an acid scavenger, 4 providing the corresponding intramolecular allylation product, oxasilacycle 2, in good yield. While levels of 1,4-stereoinduction were modest and rather substrate-dependent, 1,3-induction was consistently excellent; thus of the four possible diastereoisomeric products, only two were ever observed. We postulate that the adoption of reactive conformations in which the dipoles across the polar C-O and C=O bonds are opposed, are responsible for the high levels of 1,3-induction, 5 and that more subtle steric effects likely govern the 1,4-induction. 6 Acyclic dienes, 3, were also obtained as side-products in these allylations. We believe that these products arise through a cascade process initiated by premature cleavage of the silyl ether tether in the collapse of the initially formed carbocationic intermediate. 7 This transformation provides an acyclic allylsilane which then undergoes a vinylogous silicon-mediated olefination 8 to provide the observed diene product. 9Replacing the allylsilane nucleophile in our cyclisation precursor with a propargylsilane would provide aldehyde 4. In analogy with the reaction of aldehyde 1, exposure of 4 to a Lewis acid should effect an intramolecular allenylation to provide a novel oxasilacycle, 5, containing one new stereogenic centre and an allenylsilane moiety, which is ripe for further elaboration (Scheme 2). 10 We reasoned that such a reaction should be highly selective for a single stereoisomer since the formation of the allene moiety in 5 removes the issue of 1,4-stereoinduction, which had proven to be only modest in our previous allylation study (see Scheme 1). 3 This leaves just the issue of 1,3-induction to be considered. Since the factors governing the formation of this new carbinol stereocentre should be the same as those in our allylation study, a similar level and sense of 1,3-induction ought to be observed. Furthermore, since the silyl tether should be less efficient in stabilising the positive charge in the oxasilacyclic intermediate 6, 11 the likelihood of premature tether collapse, resulting in the Scheme 1 Reaction of an allylsilane tethered thr...

show abstract

Cleavage of vinyl carbon-silicon bond with tetrabutylammonium fluoride

Cited by 69 publications

References 30 publications

Synthesis and Reactivity of Silylformylation Products Derived from Alkynes

Synthesis and Reactivity of Silylformylation Products Derived from Alkynes

Tetra-n-butylammonium Fluoride

Using a Temporary Silicon Connection in a Highly Stereoselective Synthesis of a New Class of Cyclic Allenylsilanes

Contact Info

Product

Resources

About