An efficient ferrocene‐derived bifunctional phosphine‐catalyzed enantioselective oxa‐[4+2] cycloaddition of α‐substituted allenones with a broad range of enones is investigated for the preparation of stereodefined dihydropyrans in good to excellent yields (up to 99 %) and excellent enantioselectivity (up to 99 % ee). Furthermore, a series of valuable chiral polyheterocyclic frameworks can be efficiently
研究了有效的
二茂铁衍生的双官能膦催化的对映体选择性氧杂[4 + 2]环加成的α-取代的异
戊烯与多种烯酮,以良好的产率(高达99%)和优异的制备了立体定义的二氢
吡喃。对映选择性(高达99%ee)。此外,可以以良好的收率和优异的对映选择性有效地获得一系列有价值的手性多杂环骨架。