作者:Philippe Couture、David L. Pole、John Warkentin
DOI:10.1039/a700169j
日期:——
The formal insertion of dimethoxycarbene (1a) into the acidic
C–H bond of pentane-2,4-dione (9a), methyl acetoacetate (9b),
3-methylpentane-2,4-dione (9c) and 1,3-diphenylpropane-1,3-dione (9d) is
reported as well as the insertion of 3-benzoyloxazolidin-2-ylidene (1b)
into 9c. The β-dicarbonyl compounds 9 are known to be
equilibrated with their corresponding enols in benzene solution and the
insertions appear to proceed by proton abstraction from the enol
tautomers of 9 to generate enolate anions and either a dimethoxymethyl
cation (from 1a) or a 3-benzoyloxazolidin-2-ium cation (from 1b).
Collapse of these ion pairs at the carbon atom of the enolate yields the
major product. Formal insertion of 1a into the O–H bond of the
enol tautomer of anthrone (12) is also reported.
据报道,二甲氧基羰基(1a)正式插入戊烷-2,4-二酮(9a)、乙酰乙酸甲酯(9b)、3-甲基戊烷-2,4-二酮(9c)和 1,3-二苯基丙烷-1,3-二酮(9d)的酸性 C-H 键,以及 3-苯甲酰恶唑烷-2-亚基(1b)插入 9c。β-二羰基化合物 9 与相应的烯醇在苯溶液中处于平衡状态,插入似乎是通过从 9 的烯醇同系物中抽取质子来生成烯醇阴离子和二甲氧基甲基阳离子(来自 1a)或 3-苯甲酰恶唑啉-2-鎓阳离子(来自 1b)。 这些离子对在烯醇的碳原子上塌缩产生主要产物。此外,还报道了 1a 正式插入蒽酮 (12) 的烯醇同系物的 O-H 键的情况。