ChemInform Abstract: On the Lewis Acid-Catalysed Reaction of the 2,3-Bis(trimethylstannyl)- 1-alkene Moiety with Aldehydes.

ChemInform ◽  
2010 ◽  
Vol 22 (38) ◽  
pp. no-no
Author(s):  
T. N. MITCHELL ◽  
U. SCHNEIDER ◽  
K. HEESCHE-WAGNER
Keyword(s):  
Lewis Acid ◽  
Catalysed Reaction

Lewis acid-catalysed reaction of (cyclo)alkenes with oxiranes

2000 ◽  
Vol 41 (9) ◽  
pp. 1483-1486 ◽  
Author(s):  
David Munro ◽  
Chris Newman
Keyword(s):  
Lewis Acid ◽  
Catalysed Reaction

Lewis-Acid-Catalysed Reaction of 3-Hydroxy-2-oxindoles with Terminal Alkynes: Synthetic Approaches to the Pyrroloindoline Alkaloids

2017 ◽  
Vol 2017 (21) ◽  
pp. 3078-3091 ◽  
Author(s):  
Lakshmana K. Kinthada ◽  
K. Naresh Babu ◽  
Dikshaa Padhi ◽  
Alakesh Bisai
Keyword(s):  
Lewis Acid ◽  
Terminal Alkynes ◽  
Catalysed Reaction ◽  
Synthetic Approaches

On the Lewis acid-catalysed reaction of the 2,3-bis(trimethylstannyl)-1-alkene moiety with aldehydes

1991 ◽  
Vol 411 (1-2) ◽  
pp. 107-120 ◽  
Author(s):  
Terence N. Mitchell ◽  
Ulrich Schneider ◽  
Kerstin Heesche-Wagner
Keyword(s):  
Lewis Acid ◽  
Catalysed Reaction

Formation of 2,2-disubstituted 1,3-cyclopentanediones from ketals with 1,2-bis(trimethylsilyloxy)cyclobutene

1993 ◽  
Vol 71 (9) ◽  
pp. 1311-1318 ◽  
Author(s):  
Yong-Jin Wu ◽  
Dean W. Strickland ◽  
Tracy J. Jenkins ◽  
Pei-Ying Liu ◽  
D. Jean Burnell
Keyword(s):  
Double Bond ◽  
Carbonyl Group ◽  
Lewis Acid ◽  
Steric Hindrance ◽  
Catalysed Reaction ◽  
Carbon Double Bond ◽  
Direct Formation

The direct formation of 2,2-disubstituted 1,3-cyclopentanedione compounds by a Lewis acid catalysed reaction with 1,2-bis(trimethylsilyloxy)cyclobutene proceeds in good to excellent yields with unhindered ketals, but steric hindrance reduces the yields considerably. A carbonyl group α or β to the ketal, or a carbon–carbon double bond α to the ketal, stops the reaction completely. Orthoesters do not give geminally acylated products in synthetically useful yields.

Selective chemistry of tripentaerythritol — Synthesis of acetals and their derivatives

2006 ◽  
Vol 84 (4) ◽  
pp. 516-521 ◽  
Author(s):  
Hussein Al-Mughaid ◽  
T Bruce Grindley
Keyword(s):  
Lewis Acid ◽  
Chemical Shifts ◽  
X Ray ◽  
Nmr Chemical Shifts ◽  
X Ray Crystallography ◽  
Catalysed Reaction ◽  
Toluenesulfonic Acid ◽  
C Nmr

Tripentaerythritol was converted efficiently into 2′,2′′:6′,6′′:10′,10′′-tri-O-cyclohexylidene-2,2,6,6,10,10-hexakis(hydroxymethyl)-4,8-dioxa-1,11-undecandiol (4) by the toluenesulfonic acid catalysed reaction with cyclohexanone in a mixture of N,N-dimethylformamide and benzene. Reaction of tripentaerythritol with benzaldehyde under similar conditions gave an easily separated mixture of the four possible stereoisomers. Structures of these stereoisomers were assigned based on 1H and 13C NMR chemical shifts using trends previously observed for the dibenzylidene acetals of dipentaerythritol, whose structures had been established unambiguously by X-ray crystallography. It was found that reduction of the mixture of benzylidene acetals to 2,6,10-tris(benzyloxymethyl)-4,8-dioxa-1,11-undecanediol could be accomplished using triethylsilane with ethylaluminium dichloride as the Lewis acid after a number of commonly used conditions for this transformation failed.Key words: pentaerythritol, tripentaerythritol, dipentaerythritol, acetals, benzylidene acetals, reduction.

Enolic Ortho Esters. VIII Synthesis of (2S,3S)-2,3-Bis(methoxymethyl)-1,4,6-trioxaspiro[4.5]dec-7-ene

1998 ◽  
Vol 51 (11) ◽  
pp. 1025 ◽  
Author(s):  
David J. Collins ◽  
Ian T. Crosby
Keyword(s):  
Lewis Acid ◽  
Ortho Ester ◽  
Keto Ester ◽  
Catalysed Reaction ◽  
Ketene Acetal ◽  
Ortho Esters

Enolic ortho ester (2S,3S)-2,3-bis(methoxymethyl)-1,4,6-trioxaspiro[4.5]dec-7-ene (10b) was synthesized in 65% yield by cycloadditon of acrolein with the ketene acetal (4S,5S)-4,5-bis(methoxymethyl)-2-methylidene-1,3-dioxolan (7), derived by potassium t-butoxide treatment of (4S,5S)-4,5-bis(methoxy- methyl)-1,3-dioxolan (4). Lewis acid catalysed reaction (TiCl4, CH2Cl2, –78°) of the enolic ortho ester (10b) with the ketene silyl acetal 3-phenylmethyl-2-trimethylsilyloxy-4,5-dihydrofuran (15) afforded the formyl keto ester 3-[4′,5′-bis(methoxymethyl)-2′-(4′′-oxobutyl)-1′,3′-dioxolan-2′-yl]-3-phenylmethyl-4,5-dihydrofuran-2(3H)-one (16) (39%) with only poor diastereoselectivity. Attempts to make the bis(phenylmethyl) analogue (10a) of enolic ortho ester (10b) were thwarted by the finding that the required ketene acetal (9), analogous to (7), could not be generated by elimination from (4S,5S)-2-bromomethyl-4,5-bis(phenylmethyl)-1,3-dioxolan (6), or from the derived phenyl selenoxide (8), under a variety of conditions.

A very short synthesis of 3-methoxyestra-1,3,5,8,14-pentaen-17-one

1989 ◽  
Vol 67 (5) ◽  
pp. 816-819 ◽  
Author(s):  
D. Jean Burnell ◽  
Yong-Jin Wu
Keyword(s):  
Lewis Acid ◽  
Catalysed Reaction ◽  
Short Synthesis

3-Methoxyestra-1,3,5,8,14-pentaen-17-one (4) was prepared from 6-methoxy-1-tetralone (8) by an efficient two-pot procedure in which the D ring was generated by the Lewis acid catalysed reaction of 1,2-bis(trimethylsiloxy)cyclobutene (5) with an appropriate ketal (10). Keywords: steroid, estrone, annellation.

Catalysis of the Quadricyclane to Norbornadiene Rearrangement by SnCl2 and CuSO4

2010 ◽  
Vol 65 (3) ◽  
pp. 347-r369 ◽  
Author(s):  
Tatyana E Shubina ◽  
Timothy Clark
Keyword(s):  
Density Functional Theory ◽  
Electron Transfer ◽  
Dft Calculations ◽  
Lewis Acid ◽  
Density Functional ◽  
Acid Base ◽  
Functional Theory ◽  
Catalysed Reaction ◽  
Base Process ◽  
Molecular Catalysts

Ab initio and density-functional theory (DFT) calculations have been used to investigate the model rearrangements of quadricyclane to norbornadiene catalysed by single CuSO4 and SnCl2 molecules. The isolated reactions with the two molecular catalysts proceed via electron-transfer catalysis in which the hydrocarbon is oxidised, in contrast to systems investigated previously in which the substrate was reduced. The even-electron SnCl2-catalysed reaction shows singlet-triplet two-state reactivity. Solvation by a single methanol molecule changes the mechanism of the rearrangement to a classical Lewis acid-base process.

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