Gem-Difluoroallyllithium: Preparation by Lithium-Halogen Exchange and Utilization in Organosilicon and Organic Synthesis.
MASSACHUSETTS INST OF TECH CAMBRIDGE DEPT OF CHEMISTRY
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GEM-Difluoroallyllithium may be generated by lithiumbromine exchange between n-butyllithium and CH2CHCF2Br at -95 degrees C using an in situ procedure. When this LiCF2CHCH2 preparation is carried out in the presence of chlorosilanes, aldehydes, ketones and esters, products of type R3SiCF2CHCH2, RCHOHCF2CHCH2, RRC-OHCF2CHCH, respectively, are formed, often in good yield. The factors determining the regioselectivity in additions to C0 of unsymmetrically substituted allylic lithium reagents are discussed. Author
- Organic Chemistry