of an O-(4-methoxybenzyl) oxime ether bearing an olefin substituent and 1-chloroanthraquinone (1-Cl-AQN) catalyst in 2-butanone under visible-light irradiation affords pyrroline via an iminyl radical intramolecular hydroimination. Mechanistic studies indicate that iminyl radical generation mainly proceeds by hydrogen abstraction of the photocatalyst from the benzyl position of the oxime. Moreover,
various N‐morpholino amides with TMPZnCl⋅LiCl (TMP=2,2,6,6‐tetramethylpiperidyl) and Mg(OPiv)2 in THF at 25 °C provides solid zinc enolates with enhanced air and moisture stability (t1/2 in air: 1–3 h) after solvent evaporation. These enolates undergo Pd‐ and Cu‐catalyzed cross‐couplings with (hetero)aryl bromides as well as allylic and benzylic halides. The arylated N‐morpholino amides were converted into
Regiodivergent hydrosilylation, hydrogenation, [2π + 2π]-cycloaddition and C–H borylation using counterion activated earth-abundant metal catalysis
作者:Riaz Agahi、Amy J. Challinor、Joanne Dunne、Jamie H. Docherty、Neil B. Carter、Stephen P. Thomas
DOI:10.1039/c8sc05391j
日期:——
The widespread adoption of earth-abundant metal catalysis lags behind that of the second- and third-row transitionmetals due to the often challenging practical requirements needed to generate the active low oxidation-state catalysts. Here we report the development of a single endogenous activation protocol across five reaction classes using both iron- and cobalt pre-catalysts. This simple catalytic
Stereoselective Syntheses of Trisubstituted Olefins via Platinum Catalysis: α-Silylenones with Geometrical Complementarity
作者:Douglas A. Rooke、Eric M. Ferreira
DOI:10.1021/ja1058197
日期:2010.9.1
The stereoselective syntheses of alpha-silylenones using catalytic PtCl(2) are reported. Via alkyne activation, alpha-hydroxypropargylsilanes are converted to (Z)-silylenones through a highly selective silicon migration. The complementary (E)-silylenones are accessed by a regioselective hydrosilylation of the ynone precursor. The synthetic utility of these compounds is demonstrated in cross-coupling
Efficient Synthesis of Acylsilanes Using Morpholine Amides
作者:Christopher T. Clark、Benjamin C. Milgram、Karl A. Scheidt
DOI:10.1021/ol0483854
日期:2004.10.1
text] A general synthesis of acylsilanes from the corresponding morpholine amides and silyllithium species is described. The use of morpholine amides is economical and prevents over-addition by the silyl nucleophile. The procedure cleanly affords acylsilanes in good yields and circumvents the use of stoichiometric copper(I) cyanide typically employed to synthesize these compounds from acid chlorides.