(3-allyloxycarbonyl-2-oxo-propylidene)triphenylphosphorane   、                                                                                      2-[2-((R)-2,2-Dimethyl-[1,3]dioxolan-4-yl)-2-oxo-ethylidene]-malonic acid dimethyl ester                                                                                                                                                              在
                                                                                                                                                                                 
仲丁基锂                                                                                                                                  作用下,
                                                                                                                以
                                                                                         
四氢呋喃                                                                                  为溶剂,
                                                                                                                                                                                        生成                                                 2-[(1S,5R)-5-Allyloxycarbonyl-2-((R)-2,2-dimethyl-[1,3]dioxolan-4-yl)-4-oxo-cyclopent-2-enyl]-malonic acid dimethyl ester   、                                                                                             
2-[(1R,5S)-5-Allyloxycarbonyl-2-((S)-2,2-dimethyl-[1,3]dioxolan-4-yl)-4-oxo-cyclopent-2-enyl]-malonic acid dimethyl ester