Synthesis and Comparison of the Reactivity of Allyl Fluorides and ...
Synthesis and Comparison of the Reactivity of Allyl Fluorides and ...
Synthesis and Comparison of the Reactivity of Allyl Fluorides and ...
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Scheme 5.4 Formation <strong>and</strong> reaction <strong>of</strong> difluoroallyllithium<br />
117<br />
Chapter Five<br />
The in situ Li-halogen exchange route to gem-(difluoroallyl) lithium, allowed <strong>the</strong><br />
difluoroallylation <strong>of</strong> aldehydes, ketones, diallylketones <strong>and</strong> an alkyl aryl ketone (Table 5.1).<br />
It was, however, noted that when substrates with more reactive carbonyls were used such as<br />
acrolein <strong>and</strong> benzaldehyde, competing n-BuLi addition became more <strong>of</strong> an issue. <strong>Allyl</strong>ation<br />
<strong>of</strong> esters was also conducted successfully affording difluoroallyl ketones in good yields.<br />
Reactant Product Yield (%)<br />
Me3SiCl Me3SiCF2CH=CH2 27<br />
Et3SiCl Et3SiCF2CH=CH2 51<br />
n-Pr3SiCl n-Pr3SiCF2CH=CH2 50<br />
PhMe2SiCl PhMe2SiCF2CH=CH2 71<br />
Me2SiCl2 Me2Si(CF2CH=CH2)2 74<br />
n-C4H9CH=O n-C4H9CH(OH)CF2CH=CH2 87<br />
(CH3)3CCH=O (CH3)3CCH(OH)CF2CH=CH2 95<br />
CH2=CH-CH=O CH2=CHCH(OH)CF2CH=CH2<br />
(CH2=CHCH(OH)C4H9-n)<br />
PhCH=O<br />
PhCH(OH)CF2CH=CH2<br />
(PhCH(OH)(CH2)3CH3)<br />
20<br />
(51)<br />
15<br />
(78)<br />
(CH3)2C=O (CH3)2C(OH)CF2CH=CH2 42<br />
(C2H5)C=O (C2H5)C(OH)CF2CH=CH2 70<br />
C5H10C=O (C5H10)C(OH)CF2CH=CH2 59<br />
PhC(O)CH3 PhC(CH3)(OH)CF2CH=CH2 73<br />
ClCH2CO2Me ClCH2C(O)CF2CH=CH2 95<br />
(CH3)2CHCO2Me (CH3)2CHC(O)CF2CH=CH2<br />
62<br />
(CH3)3CCO2Me (CH3)3CC(O)CF2CH=CH2<br />
49<br />
Table 5.1 Reactions <strong>of</strong> in situ generated gem-(difluoroallyl) lithium
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