Regioselectivity and stereoselectivity in the photodimerization of rigid and semirigid stilbenes
作者:Thomas Wolff、Friedrich Schmidt、Peter Volz
DOI:10.1021/jo00041a035
日期:1992.7
The (2-pi + 2-pi)-photodimerizations of 2-phenylindene (1), 2-(4-methoxyphenyl)indene (9), and 5,10-dihydroindeno[2,1-a]indene (2) were investigated in a variety of homogeneous and micellar solvents. Four isomeric photodimers were formed from 1 and 9: syn-head-to-tail, syn-head-to-head, anti-head-to-tail, and anti-head-to-head. Relative yields of these as well as syn/anti- and head-to-tail (ht)/head-to-head (hh) ratios were determined in various solvents and as a function of temperature. In 1 syn/anti ratios ranged from 1.07 to 1.62 and ht/hh ratios from 0.88 to 1.28. In 9 syn/anti ratios between 0.83 and 2.55 and ht/hh ratios between 0.4 and 1.2 were found; preferred formation of anti and hh products was observed in micellar solvents as expected from preorientation of reactants. Two photodimers (ht and hh) were found upon irradiation of 2. ht/hh ratios ranged from 0.89 to 1.56. The variations of these ratios can be understood on the basis of a kinetic scheme, in which individual excimer states as precursors of the respective dimers are involved.
Low-valent Niobium-mediated Synthesis of Indenes: Intramolecular Coupling Reaction of CF<sub>3</sub>Group with Alkene C–H Bond
作者:Kohei Fuchibe、Ken Mitomi、Takahiko Akiyama
DOI:10.1246/cl.2007.24
日期:2007.1
CF3 group of o-alkenyl-α,α,α-trifluorotoluenes underwent intramolecular coupling reaction with the alkene C–H bond under NbCl5/LiAlH4 system. Substituted indenes were obtained in good yields.
Synthesis of Unbridged Bis(2-R-indenyl)zirconocenes Containing Functional Groups and Investigations in Propylene Polymerization
作者:Peter Witte、Tapan K. Lal、Robert M. Waymouth
DOI:10.1021/om990083w
日期:1999.9.1
bis(2-adamantylindenyl)zirconiumdichloride. Crystallographic characterization of bis[2-(4-(dimethylamino)phenyl)indenyl] zirconiumdichloride revealed an anti conformation with a coplanar orientation of the dimethylamino substituent to the aryl ring in the solid state. The polymerization behavior of all five zirconocene dichlorides in liquid propylene was studied in the presence of MAO at various temperatures
合成并表征了五个具有2-烷基和2-芳基取代基的新的茚基锆茂金属。为了合成配体,研究了二格氏试剂1,2-双(镁甲基)苯二氯作为2-取代的茚的合成子。该方法提供了对多种官能化的2-茚基茂金属的访问,例如双(2-二茂铁基茚)二氯化锆和双(2-金刚烷基茚基)二氯化锆。双[2-(4-(二甲基氨基)苯基)茚基]二氯化锆的晶体学表征显示一种抗固态具有二甲基氨基取代基与芳基环的共面取向的构象。在不同温度下,在存在MAO的条件下,研究了五种二氧化锆在液态丙烯中的聚合行为,并将结果与已知的催化剂体系双(2-苯基茚基)二氯化锆/ MAO(M1 / MAO)进行了比较。在丙烯聚合中2-芳基茚金属茂的生产率约为100-7000 kg PP /(((Zr摩尔)h)。相反,在丙烯聚合中,(2-金刚烷烯基)金属茂表现出非常低的生产率,为6kg PP /((Zr的摩尔)h)。