A synthesis of esters, amides, and sulfones bearing a 1-cyclopentenyl group at the α-position from cyclobutanones with one-carbon ring-expansion
作者:Tsuyoshi Satoh、Yu Awata、Shingo Ogata、Shimpei Sugiyama、Masami Tanaka、Motoo Tori
DOI:10.1016/j.tetlet.2009.02.053
日期:2009.4
derived from cyclobutanones and chloromethyl p-tolyl sulfoxide, with lithium enolate of carboxylic acid tert-butyl esters, lithium enolate of carboxylic acid N,N-dimethylamides, or lithium α-carbanion of alkyl phenyl sulfones gave adducts in high yields. The adducts were treated with isopropylmagnesium chloride or ethylmagnesium chloride in dry toluene to give esters, amides, and sulfones bearing a 1-cyclopentenyl
Metal-halogen exchange-initiated intramolecular conjugate addition reactions of conjugated acetylenic esters
作者:Manning P. Cooke
DOI:10.1021/jo00076a053
日期:1993.11
The lithium-iodine exchange-initiated intramolecular conjugate addition reactions of some model gamma-iodo-alpha,beta-acetylenic esters have been examined. Product mixtures arising from proton abstraction reactions were observed in reactions leading to 5-membered ring formation. More efficient cyclizations resulted when reactions were conducted in the presence of trimethylsilyl chloride to trap intermediate allenolate ions. Allenolate ion trapping by an internal electrophilic center in 26 resulted in the highly efficient formation of bicyclic ester 27.