Competitive Gold‐Promoted Meyer–Schuster and oxy‐Cope Rearrangements of 3‐Acyloxy‐1,5‐enynes: Selective Catalysis for the Synthesis of (+)‐(
<i>S</i>
)‐γ‐Ionone and (−)‐(2
<i>S</i>
,6
<i>R</i>
)‐
<i>cis</i>
‐γ‐Irone
作者:Serena Bugoni、Valentina Merlini、Alessio Porta、Sylvain Gaillard、Giuseppe Zanoni、Steven P. Nolan、Giovanni Vidari
DOI:10.1002/chem.201502382
日期:2015.9.28
simple, highly stereoselective synthesis of (+)‐(S)‐γ‐ionone and (‐)‐(2S,6R)‐cis‐γ‐irone, two characteristic and precious odorants; the latter compound is a constituent of the essential oil obtained from iris rhizomes. Of general interest in this approach are the photoisomerization of an endo trisubstituted cyclohexene double bond to an exo vinyl group and the installation of the enone side chain through
我们报告了一种(+)-(S)-γ-紫罗兰酮和(-)-(2 S,6 R)-顺式-γ-irone的简单,高度立体选择性的合成,这两种特征性和珍贵的香精;后一种化合物是从鸢尾根茎中获得的精油的成分。此方法中普遍感兴趣的是内三取代环己烯双键的光异构化为外乙烯基,以及通过[(NHC)Au I的烯酮侧链的安装]催化的Meyer–Schuster型重排。这就需要仔细研究金催化反应的机理,并明智地选择反应条件。实际上,发现迈耶-舒斯特反应可能与oxy-Cope重排竞争。金基催化系统可以选择性地促进任何一种反应。在本系统中,单核金络合物[Au(IPr)Cl]与银盐AgSbF 6在100:1丁-2-一/ H 2 O中的结合可有效促进炔丙基的迈尔-舒斯特重排苯甲酸酯,而在无水二氯甲烷中的digold催化剂[Au(IPr)} 2(μ-OH)] [BF 4 ]选择性地促进了炔丙醇的氧-Cope重排。