Diastereoselective additions of chiral (E)-crotylsilanes to .alpha.-alkoxy and .beta.-alkoxy aldehydes. A one-step, silicon-directed tetrahydrofuran synthesis

Panek, James S.; Yang, Michael G.

doi:10.1021/ja00026a033

Cited by 116 publications

(39 citation statements)

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“…Removal of the chiral auxiliary afforded silyl-substituted tetrahydrofurans of high enantiomeric purity [23]. Panek previously reported the synthesis of almost enantiomerically pure tetrasubstituted tetrahydrofurans by a double stereodifferentiation in the Lewis acid promoted addition of chiral (E)-crotylsilanes to (S)-(benzy1oxy)propanal [24].…”

Section: Scheme 12mentioning

confidence: 99%

Cycloadditions of allylsilances. Part 10. Stereoselective Construction of Ring Systems by Cycloaddition Reactions of allyltriisopropylsilance

Knölker

1997

J. Prakt. Chem.

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Allyltriisopropylsilane is a useful reagent for the stereoselective construction of various ring systems by Lewis acid promoted formal cycloaddition reactions. The reaction of allyltriisopropylsilane as a synthetic equivalent of a 1,3‐dipole in [3+2] and [3+3] cycloadditions provides cyclopentanes, tetrahydrofurans, and tetrahydronaphthalenes. [2+2] and [2+3] Cycloadditions of allyltriisopropylsilane as a synthetic equivalent of a 1,2‐dipole provide cyclobutanes, oxetanes, azetidines, and dihydrofurans.

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Section: Scheme 12mentioning

confidence: 99%

Cycloadditions of allylsilances. Part 10. Stereoselective Construction of Ring Systems by Cycloaddition Reactions of allyltriisopropylsilance

Knölker

1997

J. Prakt. Chem.

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“…24 The formal [3+2] cycloaddition involves a stereospecific cationic 1,2-silyl shift. Cationic 1,2-silyl shifts were observed previously in other reactions of organosilicon compounds, [38][39][40][41][42][43][44][45] e.g. in the related [3+2] cycloaddition of allenylsilanes to give silylcyclopentenes reported by Danheiser et al [46][47][48][49][50] The stereochemical assignment of bicyclo[4.…”

Section: Synthesis Of Silylbicyclo[n30]alkanesmentioning

confidence: 88%

Cycloadditions of Allylsilanes - Part 22.¹ Stereoselective Synthesis of Cyclopentanes and Cyclobutanes by Lewis Acid Promoted [3+2] and [2+2] Cycloadditions of Allylsilanes

Schmidt¹,

Knölker²

2010

Synlett

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“…This synthesis was only possible because of the difference in reactivity between 1 b and the allylic silane formed in situ (cf. 6 ) and between that of the two aldehydes 16…”

Section: Methodsmentioning

confidence: 97%

Bimetallic Reagents of Silicon: One‐Pot Synthesis of 2,3,5‐Trisubstituted Tetrahydrofurans by a Double Sakurai–Hosomi Reaction

Sarkar¹,

Haque²,

Basak³

2004

Angewandte Chemie

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Unsaturated bimetallic reagents containing Group 14 metals, such as silicon and tin, have recently emerged as versatile coupling reagents in organic synthesis. [1, 2] These reagents are particularly appealing when both metals employ a "ferryman" service to yield metal-free cyclic products in a one-pot reaction. However, examples of such reactions are rare. [2] As part of our interest in allyl organometallic compounds of silicon, [3] we envisioned that 1-silylmethyl allylic silanes 1 could be useful synthetic building blocks. In the presence of a Lewis acid, a bis-silyl reagent such as 1 affords a b-silyl carbocation 2 (Scheme 1) when treated with an aldehyde. This carbocation may then collapse to give an oxetane 3 (path a) [4] or, more likely, undergo a 1,2-silyl migration to give the thermodynamically favored bis-b-silyl carbocation 4, [5] which produces a trisubstituted tetrahydrofuran 5 (path b).[6] The latter was realized recently by Peng and Woerpel. [7] Additionally, a third pathway is also conceivable wherein 2 collapses to give a new allylic silane 6. The allylic silane 6 should be less reactive than the starting allylic silane 1 because its p bond is more hindered. Introduction of a second aldehyde should yield a silicon-free tetrahydrofuran 8 by trapping of the oxocarbenium ion 7 (path c). While our studies were in progress Smitrovich and Woerpel [8] reported a single experiment on the synthesis of a tetrahydrofuran lacking silyl groups by reaction of a substituted silylmethyl allylic silane and an aldehyde; however, a pure product could not be obtained and a furan structure was only tentatively assigned. Herein, we provide the first report that silylmethyl allylic silanes of type 1 can be channeled through path c to yield only 2,3,5-trisubstituted tetrahydrofurans.As the 1-silylmethyl allylic silanes 1 a,b (Scheme 2) selected for our study are novel, there were no reported procedures for their synthesis. Smitrovich and Woerpel experienced great difficulties in preparing similar compounds but eventually succeeded by employing allylic displacement, [9] which unfortunately could not be applied in our case since only carbamates from secondary allyl alcohols are amenable to it. Thus, a convenient synthetic methodology to this family of allylic silanes was our initial task. Our successful route (Scheme 2) involved heating disilanyl ether 9 (prepared in

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Diastereoselective additions of chiral (E)-crotylsilanes to .alpha.-alkoxy and .beta.-alkoxy aldehydes. A one-step, silicon-directed tetrahydrofuran synthesis

Cited by 116 publications

References 0 publications

Cycloadditions of allylsilances. Part 10. Stereoselective Construction of Ring Systems by Cycloaddition Reactions of allyltriisopropylsilance

Cycloadditions of allylsilances. Part 10. Stereoselective Construction of Ring Systems by Cycloaddition Reactions of allyltriisopropylsilance

Cycloadditions of Allylsilanes - Part 22.¹ Stereoselective Synthesis of Cyclopentanes and Cyclobutanes by Lewis Acid Promoted [3+2] and [2+2] Cycloadditions of Allylsilanes

Bimetallic Reagents of Silicon: One‐Pot Synthesis of 2,3,5‐Trisubstituted Tetrahydrofurans by a Double Sakurai–Hosomi Reaction

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