Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, USA.
J Org Chem. 2011 Apr 1;76(7):2094-101. doi: 10.1021/jo1024392. Epub 2011 Feb 28.
A wide variety of stabilized carbanions have been found to participate as nucleophiles in intramolecular Michael-type conjugate additions to in situ generated nitrosoalkenes to form bridged carbocyclic systems. The vinylnitroso platforms for these cyclizations have been prepared via two key steps involving ring-closing metathesis of vinyl chlorides and regioselective conversion of vinyl chlorides to α-chloroketones with sodium hypochlorite in glacial acetic acid/acetone. An alternative approach to preparation of some cyclization substrates has involved use of more reactive enol ethers as precursors to the requisite α-chloroketones. A sulfonamide anion has also been found to be an effective nucleophile in this type of reaction, leading to formation of a 6-azabicyclo[3.2.1]octane.
已发现多种稳定的碳负离子作为亲核试剂参与原位生成的亚硝烯的分子内迈克尔型共轭加成反应，以形成桥环碳环系统。这些环化反应的乙烯基亚硝基平台是通过两个关键步骤制备的，涉及涉及在冰醋酸/丙酮中使用环戊二烯基氯的闭环复分解和用次氯酸钠对乙烯基氯进行区域选择性转化为α-氯代酮。一种替代的方法来制备一些环化底物的方法涉及使用更具反应性的烯醇醚作为所需的α-氯代酮的前体。磺酰胺阴离子也被发现是此类反应中的有效亲核试剂，导致形成 6-氮杂双环[3.2.1]辛烷。
