Highly Regio- and Stereoselective Cyclic Iodoetherification of 4,5-Alkadienols. An Efficient Preparation of 2-(1′(Z)-Iodoalkenyl)tetrahydrofurans
摘要:
In this paper, an efficient way to synthesize 2-(1'(Z)-iodoalkenyl)tetrahydrofurans from 4,5-alkadienols and 12 was developed. The reaction of the 4,5-allenols with a substituent in the 3-position afforded the trans-2,3-disubstituted tetrahydrofurans with very high diastereoselectivity. However, when the axially optically active 4,5-allenol was treated with 12 in n-hexane, the efficiency for chirality transfer was low. This problem was circumvented by conducting the reaction in CH2Cl2 at room temperature and applying N-iodosuccinimide as the electrophilic reagent; however, the Z/E ratio for the products is much lower. Highly optically active Z-products may be prepared via the kinetic resolution via a Sonogashira coupling reaction with propargyl alcohol.
Highly Regio- and Stereoselective Cyclic Iodoetherification of 4,5-Alkadienols. An Efficient Preparation of 2-(1′(Z)-Iodoalkenyl)tetrahydrofurans
摘要:
In this paper, an efficient way to synthesize 2-(1'(Z)-iodoalkenyl)tetrahydrofurans from 4,5-alkadienols and 12 was developed. The reaction of the 4,5-allenols with a substituent in the 3-position afforded the trans-2,3-disubstituted tetrahydrofurans with very high diastereoselectivity. However, when the axially optically active 4,5-allenol was treated with 12 in n-hexane, the efficiency for chirality transfer was low. This problem was circumvented by conducting the reaction in CH2Cl2 at room temperature and applying N-iodosuccinimide as the electrophilic reagent; however, the Z/E ratio for the products is much lower. Highly optically active Z-products may be prepared via the kinetic resolution via a Sonogashira coupling reaction with propargyl alcohol.
Progress in Carbonylative [2+2+1] Cycloaddition: Utilization of a Nitrile Group as the π Component
作者:Takashi Iwata、Fuyuhiko Inagaki、Chisato Mukai
DOI:10.1002/anie.201305729
日期:2013.10.11
New tricks, old reactions: The treatment of 2‐(1,2‐propadienyl)phenylacetonitrile derivatives with a catalytic amount of [RhCl(CO)dppp}2] (dppp=1,3‐bis(diphenylphosphanyl)propane) under a CO atmosphere produced benzo[f]oxyindole derivatives (see scheme). This aza‐Pauson–Khand‐type reaction was applicable to aliphatic substrates, thus resulting in the formation of the azabicyclo[3.3.0]octadienone derivatives
新的技巧,旧的反应:在催化条件下处理催化量为[RhCl(CO)dppp} 2 ](dppp = 1,3-‐双(二苯基膦基)丙烷的2-(1,2-丙二烯基)苯基乙腈衍生物CO气氛下生成苯并[ f ]氧基吲哚衍生物(参见方案)。该aza-Pauson-Khand型反应适用于脂肪族底物,从而导致形成azabicyclo [3.3.0] octadienone衍生物。