Synthetic Studies toward Anisatin: A Formal Synthesis of (±)-8-Deoxyanisatin
摘要:
[GRAPHICS]An efficient strategy to construct the congested C-7a quaternary chiral center of anisatin was developed, by way of an Eschenmoser-Claisen rearrangement, Conversion of the resultant amide to Kende's epsilon -lactone intermediate 3 in four steps completed a concise formal synthesis of (+/-)-8-deoxyanisatin (2).
development of novel carbonylative transformations usingCOsurrogates. Consequently, toxic CO gas can be replaced by more convenient inorganic or organic carbonyl compounds. Herein, the first regioselectivemethoxycarbonylation of alkenes with paraformaldehyde and methanol as CO substitutes is reported. This new procedure is applicable to a series of alkenes in the presence of a palladium catalyst under
report a general and efficient Pd-catalysed alkoxycarbonylation of sterically hindered and demanding olefins including a variety of tri-, tetra-substituted and 1,1-disubstituted alkenes. In the presence of 1,3-bis(tert-butyl(pyridin-2-yl)phosphanyl)propane L3 or 1,4-bis(tert-butyl(pyridin-2-yl)phosphanyl)butane L4 the desired esters are obtained in good yields and selectivities. Similar transformation
A general and selective palladium-catalyzed alkoxycarbonylation of all kinds of alkenes with formic acid (HCOOH, FA) is described. Terminal, di-, tri-, and tetra-substituted including functionalized olefins are converted into linear esters with high yields and regioselectivity. Key-to-success is the use of specific palladium catalysts containing ligands with built-in base, e.g., L5. Comparison experiments
A Conjugate Addition of Arylboronic Acids to<i>α,β</i>-Unsaturated Carbonyl Compounds Catalyzed by 2<i>β</i>-CD-[Rh(OH)(cod)]<sub>2</sub>or [RhCl(cod)]<sub>2</sub>in a Single Aqueous Medium
作者:Ryoh Itooka、Yuki Iguchi、Norio Miyaura
DOI:10.1246/cl.2001.722
日期:2001.7
The rhodium-catalyzed conjugate addition of tolylboronic acid to α,β-unsaturated ketones, esters or amides was carried out in water. [RhCl(cod)]2 and 2β-cyclodextrin-[Rh(OH)(cod)]2 complexes were found to catalyze the reaction efficiently in a single aqueous medium.
Rhodium-Catalyzed 1,4-Addition of Arylboronic Acids to α,β-Unsaturated Carbonyl Compounds: Large Accelerating Effects of Bases and Ligands
作者:Ryoh Itooka、Yuki Iguchi、Norio Miyaura
DOI:10.1021/jo0207067
日期:2003.7.1
phosphine derivatives. The reaction was further accelerated in the presence of KOH, thus allowing the 1,4-addition even at 0 degrees C. A cationic rhodium(I)-(R)-binap complex, [Rh(R-binap)(nbd)]BF(4), catalyzed the reaction at 25-50 degrees C in the presence of Et(3)N with high enantioselectivities of up to 99% ee for alpha,beta-unsaturated ketones, 92% for aldehydes, 94% for esters, and 92% for amides.