Biarylphosphonite Gold(I) Complexes as Superior Catalysts for Oxidative Cyclization of Propynyl Arenes into Indan-2-ones
作者:Guilhem Henrion、Thomas E. J. Chavas、Xavier Le Goff、Fabien Gagosz
DOI:10.1002/anie.201301015
日期:2013.6.10
Striking gold: A series of variously functionalized propynyl arenes was smoothly converted into indan‐2‐ones by a new gold(I)‐catalyzed oxidative cyclization process. [LAu]NTf2 (Tf=trifluoromethanesulfonyl) is a superior catalyst both in terms of yield and kinetics for the present transformation.
打击金:通过新的金(I)催化的氧化环化工艺,一系列功能化的丙炔基芳烃被顺利转化为茚满-2-酮。就本转化而言,就收率和动力学而言,[ L Au] NTf 2(Tf =三氟甲磺酰基)是优良的催化剂。
An Atom-Economical Access to β-Heteroarylated Ketones from Propargylic Alcohols via Tandem Ruthenium/Indium Catalysis
作者:Barry M. Trost、Alexander Breder
DOI:10.1021/ol102706j
日期:2011.2.4
The direct and chemoselective synthesis of β-heteroarylated ketonesfrom secondary propargyl alcohols through tandem Ru/In catalysis is reported. Both electron-rich and neutral heteroarenes, such as furans and indoles, efficiently undergo the redox isomerization/conjugate addition (RICA) sequence to provide the corresponding adducts in yields of up to 97%.
Improvement process for debrominative rearrangements
申请人:MERRELL DOW PHARMACEUTICALS INC.
公开号:EP0370153A1
公开(公告)日:1990-05-30
This invention relates to an improvement in the standard procedures involving a debrominative rearrangement reaction of a terminal dibromoolefin with activated magnesium in tetrahydrofuran.
bromine/lithium and bromine/zinc exchangereactions take place preferentially at the sterically more hindered bromine atom of the starting gem-dibromo compounds. The observation is rationalized by an exchange mechanism involving a linear transition state of either an ate complex formation or an SN2 reaction at the more hindered bromine atom where strain relief due to the elongation of the carbon-bromine bond is
通过宝石的溴/金属交换反应生成锂和锌酸类胡萝卜素的立体化学已经研究了分别与BuLi和三有机锌酸锂形成的二溴化合物。已证明,衍生自1,1-二溴烯烃的锂和锌酸酯类化合物在低温下是构型稳定的,而在未反应的起始二溴烯烃的存在下,锂类化合物而不是锌酸酯类化合物在类胡萝卜素碳上容易进行异构化。在起始二溴环丙烷存在下,衍生自1,1-二溴环丙烷的Zincate类胡萝卜素在类胡萝卜素碳上缓慢进行异构化。事实证明,锂和锌酸盐类胡萝卜素的异构化反应是通过涉及类胡萝卜素与起始二溴化合物之间的溴/金属交换的机理进行的。在1,1-二溴烯烃在热力学条件下的反应中观察到锂类胡萝卜素的高度立体选择性形成。在动力学控制的条件下,溴/锂和溴/锌的交换反应均优先发生在起始位点的空间受阻溴原子上宝石-二溴化合物。通过交换机制合理化该观察,该交换机制涉及在受阻溴原子处的盐配合物形成或S N 2反应的线性过渡态,在这种情况下,由于碳-溴键的延长,应力会减轻。
A general and convenient synthetic method of geometrically pure (Z)-1-bromo-1-alkenes
Palladium catalyzed hydrogenolysis of 1,1-dibromo-1-alkenes by tributyltin hydride proceeds smoothly to give (Z)-1-bromo-1-alkenes with excellent stereoselectivity in good yields. Dibromomethylenation of aldehydes by a combination of CBr4 and Ph3P in methylene chloride and the successive hydrogenolysis affords (Z)-1-bromo-1-alkenes in one-pot.