Nucleophilicity vs Basicity in the Reaction of Sodium tert-Butoxide with -Stannyl Ketones
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- 作者：Alicia B. Chopa and Ana P. Murray
- 刊名：Organometallics
- 出版年：2001
- 出版时间：April 2, 2001
- 年：2001
- 卷：20
- 期：7
- 页码：1476 - 1478
- 全文大小：47K
- 年卷期：v.20,no.7(April 2, 2001)
- ISSN：1520-6041
文摘
The reaction of 3-stannyl-1,2,3-triphenyl- and3-stannyl-1,3-diphenyl-2-methylpropanones with sodiumtert-butoxide in either t-BuOH or dimethyl sulfoxide(DMSO) as solvent leads to elimination and/or substitution products. The composition of the product mixturesdepends essentially on the nature of the ligands attachedto the tin atom, on the solvent, and also on the nature ofthe substituent on C-2. Thus, 
beta2.gif" BORDER=0 ALIGN="middle">-(triphenyl), beta2.gif" BORDER=0 ALIGN="middle">-(bromodiphenyl), and beta2.gif" BORDER=0 ALIGN="middle">-(trichlorostannyl) ketones undergo anexclusive elimination reaction leading to an unsaturatedketone in good to high yields (72%-96%) both in t-BuOHand in DMSO. In the latter the reactions lead to higheryields in shorter times. On the other hand, beta2.gif" BORDER=0 ALIGN="middle">-(trimethylstannyl) ketones lead to mixtures of olefins and substitution products in t-BuOH and exclusively to substitution products in DMSO (96%-98%). Stereochemicalresults suggest that the elimination reactions proceedthrough an (E1cB)R mechanism.
beta2.gif" BORDER=0 ALIGN="middle">-(triphenyl), beta2.gif" BORDER=0 ALIGN="middle">-(bromodiphenyl), and beta2.gif" BORDER=0 ALIGN="middle">-(trichlorostannyl) ketones undergo anexclusive elimination reaction leading to an unsaturatedketone in good to high yields (72%-96%) both in t-BuOHand in DMSO. In the latter the reactions lead to higheryields in shorter times. On the other hand, beta2.gif" BORDER=0 ALIGN="middle">-(trimethylstannyl) ketones lead to mixtures of olefins and substitution products in t-BuOH and exclusively to substitution products in DMSO (96%-98%). Stereochemicalresults suggest that the elimination reactions proceedthrough an (E1cB)R mechanism.