21681-63-0Relevant academic research and scientific papers
New Methods for Stereoselective Synthesis of α-Alkylidene-γ-butyrolactones Using Monoanion of O-Ethyl S-(Tetrahydro-2-oxo-3-furanyl) Thiocarbonate and Dianion of α-Mercapto-γ-butyrolactone
Tanaka, Kazuhiko,Uneme, Hideki,Yamagishi, Nobuyuki,Tanikaga, Rikuhei,Kaji, Aritsune
, p. 2910 - 2916 (1980)
The lithium enolates of O-ethyl S-(tetrahydro-2-oxo-3-furanyl) dithiocarbonate and thiocarbonate were found to be efficient reagents for the stereoselective synthesis of α-alkylidene-γ-butyrolactones from carbonyl compounds.The dianion of α-mercapto-γ-butyrolactone was successfully generated by treatment of α-mercapto-γ-butyrolactone with 2.2 equivalents of lithium diisopropylamide in the presence of N,N,N',N'-tetramethylethylenediamine at -78 deg C in THF.The dianion thus formed has been utilized for the efficient and stereoselective synthesis of α-alkylidene-γ-butyrolactones from carbonyl compounds.
A Two-Step Preparation of α-Alkylidene γ-Lactones from γ-Lactones: A Synthesis of (+/-)-Ancepsenolide
Larson, Gerald L.,Perez, Rosa M. Betancourt de
, p. 5257 - 5260 (2007/10/02)
γ-Butyrolactone, γ-valerolactone, and the cis lactone of 2-hydroxycyclohexaneacetic acid have been C-silylated via their respective lithium enolates with diphenylmethylchlorosilane.The resulting α-silylated γ-lactones can be deprotonated and condensed with aldehydes and ketones to give α-alkylidene γ-lactones in moderate to excellent yield.The enolate of the α-diphenylmethylsilyl cis lactone of 2-hydroxycyclohexaneacetic acid condensed with 1-butanal but not with benzaldehyde or acetaldehyde.
