important biologically active compounds. Synthesis of a series of tricyclic benzopyrans derivatives via N-Heterocycliccarbene (NHC) catalyzedannulation of enals to α-methylidenetetralones/chromanones is described. This reaction afforded the benzopyrans in high yield with aromatic as well as aliphatic enals.
Synthesis of β-mercuri ketones by the reaction of siloxycyclopropanes with mercuric acetate and their conversion to α-methylene ketones and γ-ketoesters
Siloxycyclopropanes were quantitatively converted to β-acetoxymercuri ketones by the reaction with mercuricacetate. Successive treatment with palladium chloride or palladium chloride/carbon monoxide gave α-methylene ketones or γ-ketoesters, respectively, in good yields.
Enolate alkylation with bromomethyl sulphides: synthesis of α-methylene ketones and carboxylic acids
作者:Hans J. Reich、James M. Renga
DOI:10.1039/c39740000135
日期:——
Alkylation of ketone and carboxylate enolates with benzyl bromomethylsulphide, followed by sulphoxide elimination, gives α-methyleneketones and carboxylicacids.
用苄基溴甲基硫化物将酮和羧酸酯烯酸酯烷基化,然后亚砜消除,得到α-亚甲基酮和羧酸。
A new Fragmentation Reaction of .GAMMA.-Oxosulfonium Methylides.
Reactions of sulfonium methylides attaches to a 5- or 6-membered cycloalkanone undergo the ring-fission as a major reaction course to give α-methylene-ω-(phenylthio)carboxylates, whereas sulfonium methylides attached to a larger ring give α-methylenecycloalkanones predominantly. Reactions of the acyclic compounds are also examined
Mercurinium ion mediated ring expansion of 1- alkenyl-1-cycloalkanols
作者:Sunggak Kim、Kee Han Uh
DOI:10.1016/s0040-4039(00)74251-1
日期:1992.7
TMS ethers of 1-alkenyl-1-cycloalkanols readily rearranged to the ring expanded β-mercurio cycloalkanones via mercurinium ions, which could be converted into α-methylene cycloalkanones through elimination and further one carbon expanded cycloalkanones via free radical chain reactions.