Bismuth Triflate-Catalyzed Vinylogous Nucleophilic 1,6-Conjugate Addition of <i>para</i>-Quinone Methides with 3-Propenyl-2-silyloxyindoles
作者:Kai-Xue Xie、Zhi-Pei Zhang、Xin Li
DOI:10.1021/acs.orglett.7b03433
日期:2017.12.15
A highlydiastereoselective vinylogous nucleophilic 1,6-conjugate addition reaction of para-quinone methides with 3-propenyl-2-silyloxyindoles by a bismuth triflate catalyst has been developed. A number of diphenylmethane type compounds functionalized with oxindole motifs was obtained with excellent yields (up to 99%) and very good diastereoselectivities (up to Z/E > 99:1).
已经开发了三氟甲磺酸铋催化剂对对醌甲基化物与3-丙烯基-2-甲硅烷氧基吲哚的高度非对映选择性的乙烯基亲核性1,6-共轭加成反应。获得了许多具有羟吲哚基序官能化的二苯甲烷类化合物,具有优异的收率(高达99%)和非常好的非对映选择性(高达Z / E > 99:1)。
3-Alkenyl-2-silyloxyindoles in Vinylogous Mannich Reactions: Synthesis of Aminated Indole-Based Scaffolds and Products
The first Lewis acid catalyzed vinylogous Mukaiyama-type Mannich addition of 3-alkenyl-2-silyloxyindoles to in situ generated N-Boc imines has been established, which affords chiral alpha-alkylidene-delta-amino-2-oxindole products with good efficiency and complete gamma-site- and Z-selectivity. The reaction is wide in scope, as it can be applied with equal convenience to different silyloxyindole donors and aromatic or aliphatic aminal-derived aldimine acceptors. The utility of these scaffolds is demonstrated by their easy transformation into either spirocyclopropane oxindole,, or homotryptamine-like products, featuring nontraditional indole-based skeleton connections.