The decarboxylative E′-dehydration of β,γ-unsaturated δ-hydroxy acids with DMF-dineopentylacetal shows SYN-faciality irrespective of whether the conformation of the hydroxy group relative to the double bond axis is anticlinal or synclinal.
                                    β,γ-不饱和δ-羟基酸的去羧基化E′-脱
水反应与
DMF-
二戊基醚的反应显示出SYN面选择性,不论羟基相对于双键轴的构象是反向斜角还是同向斜角。