Neighboring group participation in Lewis acid-promoted [3 + 4] and [3 + 5] annulations. The synthesis of oxabicyclo[3.n.1]alkan-3-ones
作者:Gary A. Molander、Kimberly O. Cameron
DOI:10.1021/ja00056a002
日期:1993.2
2-(alkoxycarbon)-m-oxabicyclo[3.n.1]alkan-3-ones can be constructed by this process in which two new carbon-carbon bonds are generated. Unusually high regioncontrol is observed, and good to excellent stereochemical control can be achieved at virtually every position on the new carbocycles. Intramolecular neighboring group participation is proposed to explain the unusually high selectivities attained in the annulation
路易斯酸用作 1,4- 和 1,5- 二羰基亲电试剂与 β-二酮和 β-酮酯的双(三甲基甲硅烷基)烯醇醚环化的催化剂。多种 2-(烷氧基碳)-m-氧杂双环[3.n.1]alkan-3-ones 可以通过该过程构建,其中产生两个新的碳-碳键。观察到异常高的区域控制,并且几乎可以在新碳环的每个位置实现良好到出色的立体化学控制。提出分子内相邻基团参与来解释在环化反应中获得的异常高的选择性