Elemental iodine has been utilized as an efficient catalyst for the intramolecular[4 + 2]cycloaddition of o-quinomethanes generated in situ from o-hydroxybenzaldehydes and unsaturated alcohol in the presence of trimethyl orthoformate to afford the corresponding trans-annelated pyrano[3,2-c]benzopyrans in high yields with high diastereoselectivity
碘元素被用作一种高效催化剂,用于在
原甲酸三甲酯存在下对邻羟基
苯甲醛和不饱和醇原位生成的邻喹
甲烷进行分子内[4 + 2]环加成,从而以高产率和高非对映选择性得到相应的反式沟道化
吡喃并[3,2-c]苯并
吡喃