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Regiochemistry in the hydroboration of allylsilanes

โœ Scribed by Ian Fleming; Nicholas J. Lawrence

Book ID
104221248
Publisher
Elsevier Science
Year
1988
Tongue
French
Weight
272 KB
Volume
29
Category
Article
ISSN
0040-4039

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โœฆ Synopsis

The hydroboration of most types of allylsilane is highly selective for the formation of the product having the silicon and boron in a 1,3 relationship when the hydroborating agent is 9-BBN. There is only a low degree of correlation between the difference in the chemical shifts of the trigonal carbon atoms on an alkene and the regioselectivity in hydroboration with either borane:THF or 9-BBN. A silyl group is both large and electropositive, and both factors should cooperate to direct the hydroboration of allylsilanes to place the boron on C-3 of the ally1 unit. This expectation is supported by the observation that allyldimethyl(phenyl)silane (1) reacts with borane to give only the product (2) with the boron atom at the terminus of the ally1 unit ,2 HBR, PhMe2Si BR2 -U 2

๐Ÿ“œ SIMILAR VOLUMES

Stereochemistry in the hydroboration of
Stereochemistry in the hydroboration of allylsilanes
โœ Ian Fleming; Nicholas J Lawrence ๐Ÿ“‚ Article ๐Ÿ“… 1988 ๐Ÿ› Elsevier Science ๐ŸŒ French โš– 251 KB

The hydroboration of allylsilanes is highly stereoselective in the sense (3 -t 4 and 6 + .I), especially with 9-BBN as the hydroborating reagent. The products can be converted stereospecifically into 1,3-diol derivatives (5 and 6). Allylsilanes usually react with electrophiles in the stereochemica