Quntar AAA, Melman A, Srebnik M. Selective preparation of (E)-3-oxo-1-alkenylphosphonates by insertion of acyl chlorides and nitriles into zirconacycles.
J Org Chem 2002;
67:3769-72. [PMID:
12027692 DOI:
10.1021/jo016403e]
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Abstract
Zirconacycles 1, obtained from diethyl 1-alkynylphosphonates, insert either acyl chlorides or nitriles to provide, after acidic workup, (E)-3-oxo-1-alkenylphosphonates, 2, in isolated yields of 55-83%. Insertion produces only one regio- and stereoisomer. The reaction is quite general and proceeds well with both aliphatic and aromatic acyl chlorides. Acetonitrile and p-methoxybenzonitrile also inserted efficiently. Insertion of isobutyl chloroformate produced the vinylphosphonocarboxylate, 2c, the first representative of this class of compounds.
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