Directed Ortho Metalation of Neopentyl Benzoates with LDA: Preparation of Arylboronic Acids

Journal of Organic Chemistry

Volumn 63, Issue 7, 1998, Pages 2054-2055

  Caron, Stéphane ^a   Hawkins, Joel M ^a  

^a PFIZER INC   (United States)

Author keywords

[No Author keywords available]

Indexed keywords

EID: 0000397348     PISSN: 00223263     EISSN: None     Source Type: Journal    
DOI: 10.1021/jo972141y     Document Type: Article

References (27)

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11. For a demonstratin of the successful use of LDA as a base in directred metalation involving an intramolecular trap, see: Beaulieu, F.; Snieckus, V. J. Org. Chem. 1994, 59, 6508-6509.
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17. The metalation of benzonitrile using LTMP as a base and trimethyl borate as the electrophile has been reported. See ref 15.
18. The generation of benzophenones in the absence of in situ traps with LDA here, and in Beak's earlier work with LTMP (see ref 14) demonstrates that lithium amides are efficient kinetic bases for the deprotonation of alkyl benzoates. In particular, the benzophenone formation, and the in situ trapping by trimethylsilyl chloride, shows that a complex between LDA and the borate trap is not necessary for the ortho deprotonation of benzoate esters.
19. We have found that the hydrolyses of neopentyl esters proceed at comparable rates as ethyl esters under single-phase conditions. The results of our study of the use of neopentyl benzoates in Suzuki couplings will be reported in due course.
20. LDA was purchased from ACROS. We found no difference in yield between the commercial solution and the material freshly prepared from diisopropylamine and n-butyllithium.
21. Smith, K.; Leach, J. B. Organometallic Compounds of Boron; Chapman and Hall: New York, 1985.
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24. The single-crystal X-ray crystal structure of compound 3c was solved and is depicted in the Supporting Information.
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