Rhodium-Catalyzed Linear Cross-Trimerization of Two Different Alkynes with an Alkene and Two Different Alkenes with an Alkyne
作者:Masayuki Kobayashi、Ken Tanaka
DOI:10.1002/chem.201200903
日期:2012.7.23
paths with rhodium: A cationic RhI/H8‐BINAPcomplex has been found to catalyze the linear cross‐trimerization of terminal alkynes, acetylenedicarboxylates, and acrylamides to give substituted trienes. The asymmetric linear cross‐trimerization, giving substituted chiral dienes, has also been achieved by using monosubstituted alkenes and (R)‐BINAP instead of terminal alkynes and H8‐BINAP (see scheme;
与铑的交叉路径:阳离子Rh I / H 8 ‐BINAP络合物可催化末端炔烃,乙炔二羧酸酯和丙烯酰胺的线性交叉三聚反应,生成取代的三烯。还可以通过使用单取代的烯烃和(R)-BINAP代替末端炔烃和H 8 -BINAP(参见方案; H 8 -BINAP = 2,2'-bis )来实现不对称线性交叉三聚,得到取代的手性二烯。(二苯基膦基)-5,5',6,6',7,7',8,8'-八氢-1,1'-联萘基; BINAP = 2,2'-双(二苯基膦基)-1,1'-联萘]]。
Rhodium-Catalyzed Asymmetric Formal Olefination or Cycloaddition: 1,3-Dicarbonyl Compounds Reacting with 1,6-Diynes or 1,6-Enynes
作者:Takeshi Suda、Keiichi Noguchi、Ken Tanaka
DOI:10.1002/anie.201007727
日期:2011.5.2
A cationic rhodium(I) complex catalyzes the title reaction of 1,6‐diynes through a [2+2+2] cycloaddition and subsequent electrocyclic ring opening (see scheme; cod=1,5‐cyclooctadiene, H8‐binap=2,2′‐bis(diphenylphosphino)‐5,5′,6,6′,7,7′,8,8′‐octahydro‐1,1′‐binaphthyl). The asymmetric intramolecular [2+2+2] cycloaddition of 1,3‐dicarbonyl compounds with 1,6‐enynes was also accomplished.
Cycloisomerization is a totally atom economic procedure which converts dienes and enynes into cyclic molecules. Modification of Grubbs’ 2nd generation catalysts by reaction with dimethylformamide provides a new species able to catalyse this transformation. Selection of suitable conditions allowed high yields and selectivity. Studies performed in order to identify the catalytic species point to a non-carbenic
Bridging a gap: A cationic rhodium(I)/ligand complex catalyzes the title reaction of alkynes and amide‐linked 1,5‐dienes, leading to bridged multicyclic compounds, with high chemo‐, regio‐, and enantioselectivity (see scheme; Bn=benzyl).
A Rh-BINAP complex was used to catalyze the hetero-[2+2+2] cycloaddition of symmetrical 1,6-diynes and carbonyl moiety of ketoesters, a diketone, and an aldehyde to give bicyclic α-pyrans, which were readily transformed into monocyclic compounds via the following electrocyclic ringopening. In the reaction of an unsymmetrical 1,6-diyne and a 1,7-diyne, α-pyrans with a quaternary carbon stereocenter
Rh-BINAP 复合物用于催化对称的 1,6-二炔和酮酯、二酮和醛的羰基部分的杂-[2+2+2] 环加成反应,得到双环 α-吡喃,它们很容易转化通过以下电环开环转化为单环化合物。在不对称的 1,6-二炔和 1,7-二炔的反应中,使用手性铑催化剂以中等至优异的 ee 获得具有季碳立体中心的 α-吡喃。