The synthesis of (+/-)-histrionicotoxin has been achieved in just nine steps using a two-directional synthesis strategy. Key reactions include a two-directional cross-metathesis, a tandem oxime formation/Michael addition/1,4-prototopic shift/[3 + 2]-cycloaddition cascade, a selective Z,Z-bisenyne formation, and a one-pot N-O and bischloroacetylene reduction.
Two-directional synthesis. Part 1: A short formal synthesis of (±)-histrionicotoxin and (±)-histrionicotoxin 235A
作者:Robert A Stockman
DOI:10.1016/s0040-4039(00)01640-3
日期:2000.11
The formal synthesis of (±)-histrionicotoxin and (±)-histrionicotoxin 235A using a two-directional strategy has been accomplished. The key feature of the synthesis is a tandem oxime formation/Michael addition/nitrone cycloaddition sequence, which form the azaspiro[5.5]undecane skeleton in two operations from an acyclic symmetrical precursor.
Flow synthesis of tricyclic spiropiperidines as building blocks for the histrionicotoxin family of alkaloids
作者:Malte Brasholz、Brian A. Johnson、James M. Macdonald、Anastasios Polyzos、John Tsanaktsidis、Simon Saubern、Andrew B. Holmes、John H. Ryan
DOI:10.1016/j.tet.2010.04.092
日期:2010.8
A domino cyclization reaction of the bis-unsaturated ketone 3 with hydroxylamine proceeds with good yield and high stereoselectivity, in a flow reactor system. The tricyclic spiropiperidine products 5 and 2 obtained are valuable building blocks for the synthesis of analogues of the histrionicotoxin alkaloids. (C) 2010 Elsevier Ltd. All rights reserved.