3,5-Bis(trifluoromethyl)phenyl Sulfones for the Highly Stereoselective Julia–Kocienski Synthesis of α,β-Unsaturated Esters and Weinreb Amides
作者:Diego A. Alonso、Mónica Fuensanta、Enrique Gómez-Bengoa、Carmen Nájera
DOI:10.1002/ejoc.200800041
日期:2008.6
l)phenyl (BTFP) sulfones tert-butyl α-(BTFPsulfonyl)acetate (4) and Weinreb α-(BTFPsulfonyl)acetamide (5) have successfully been employed in the Julia–Kocienski olefination of aldehydes with K2CO3 as the base at 120 °C in DMF under solid/liquid phase-transfer catalysis conditions to afford α,β-unsaturated esters and Weinrebamides, respectively. The corresponding products were obtained in good yields
New Reagent for Convenient Access to the α,β-UnsaturatedN-Methoxy-N-methyl-amide Functionality by a Synthesis Based on the Julia Olefination Protocol
作者:Beedimane Narayana Manjunath、Neeraj P. Sane、Indrapal Singh Aidhen
DOI:10.1002/ejoc.200600126
日期:2006.6
A newreagent for the synthesis of the α,β-unsaturated N-methoxy-N-methyl-amide structural unit has been developed. 2-(Benzo[d]thiazol-2-ylsulfonyl)-N-methoxy-N-methylacetamide, a crystalline solid with an indefinite shelf life that can be easily prepared in two convenient steps from 2-chloro-N-methoxy-N-methylacetamide, reacted with a variety of aldehydes under Julia conditions to furnish the α,β-unsaturated
Synthesis of α,β-Unsaturated α′-Haloketones through the Chemoselective Addition of Halomethyllithiums to Weinreb Amides
作者:Vittorio Pace、Laura Castoldi、Wolfgang Holzer
DOI:10.1021/jo401236t
日期:2013.8.2
A straightforward synthesis of variously functionalized α,β-unsaturated α′-haloketones has been achieved through the chemoselective addition of halomethyllithium carbenoids to Weinrebamides at −78 °C. A comparative study employing the corresponding esters under the same reaction conditions pointed out that the instability of the tetrahedral intermediate formed from the latter is responsible for the
A novel route to cyclopropyl ketones, aldehydes, and carboxylic acids.
作者:Karen E. Rodriques
DOI:10.1016/s0040-4039(00)79644-4
日期:1991.3
Cyclopropanation of α,β-unsaturated N-methoxy-N-methyl amides provided the cyclopropyl amides in far superior yields to those obtained with the corresponding ketones. The desired ketones are then readily accessible by the addition of organometallicreagents. Access to a variety functional groups, including aldehydes and carboxylic acids, is also described.
Asymmetric Gold(I)‐Catalyzed Tandem Hydroarylation–Nazarov Cyclization: Enantioselective Access to Cyclopentenones
作者:Marta Solas、Samuel Suárez‐Pantiga、Roberto Sanz
DOI:10.1002/anie.202207406
日期:2022.8.26
A new enantioselective version of the Nazarov cyclization is reported. The reaction design uses readily available alkenynones to trigger a gold(I)-catalyzed anti-Michael hydroarylation of the ynone followed by Nazarov cyclization. A chiral gold complex is able to control the absolute stereochemistry of the process. Cyclopenta[c]chromenones, which combine the 2H-chromene and cylopentanone cores, are
报道了纳扎罗夫环化的新对映选择性版本。该反应设计使用容易获得的烯炔酮来触发炔酮的金(I)催化的反迈克尔加氢芳基化,然后进行纳扎罗夫环化。手性金络合物能够控制该过程的绝对立体化学。环戊[ c ]色酮结合了 2 H-色烯和环戊酮核心,合成时具有高产率和ee值。