2,3-Dimethylene-2,3-dihydrofuran is generated in situ by boron trifluoride induced 1,4-conjugative elimination of tributylstannylmethyl acetate and then trapped with dienophiles to give the corresponding Diels–Alder cycloadducts.
                                    2,3-二亚甲基-
2,3-二氢呋喃是在
硼三
氟化物诱导下,通过1,4-共轭消除反应原位生成的,然后与二烯亲体结合,形成相应的Diels–Alder环加成物。