Iron in the service of chromium: the ortho-benzannulation of trans,trans-dienyl Fischer carbene complexes.

نویسندگان

  • Yiqian Lian
  • William D Wulff
چکیده

Chromium Fischer carbene complexes with trans,trans-dienyl substituents on the carbene carbon will react with diiron nonacarbonyl to give 2-alkoxycyclohexa-2,4-dienone iron tricarbonyl complexes and/or 2-alkoxyphenols in excellent yields. In the presence of silica gel or base, the cyclohexadienone complex will suffer loss of the iron and aromatization to give 2-alkoxyphenols. The formation of 2-alkoxyphenols from dienyl chromium carbene complexes is a known process (ortho-benzannulation) that only occurs with certain cis,trans-dienyl complexes. Control experiments show that trans,trans-dienyl chromium carbene complexes do not undergo conversion to 2-alkoxyphenols in the absence of an iron source. The process most likely occurs either via coordination of the dienyl unit in the chromium carbene complex to an iron tricarbonyl group and then loss of the chromium or via direct trans-metalation of the carbene ligand to give an iron carbene complex and then internal coordination to the dienyl unit such that cis to trans isomerization of the alpha,beta-double bond occurs.

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

منابع مشابه

Alkyne competition in the benzannulation reaction with chromium carbene complexes.

The benzannulation reaction of Fischer carbene complexes is investigated under conditions where the reaction of the carbene complex is occurring in the presence of two different alkynes. A series of competition experiments are examined where the effects of various structural factors are explored by pitting 10 different carbene complexes with 11 different alkynes. Terminal alkynes will react sel...

متن کامل

Chromene chromium carbene complexes in the syntheses of naphthopyran and naphthopyrandione units present in photochromic materials and biologically active natural products.

The carbene complex 5-(2,2-dimethyl-2H-chromene)methoxylmethylene chromium pentacarbonyl will undergo a benzannulation reaction with phenylacetylene, 1-pentyne, 3-hexyne, and trimethylsilylacetylene to give 7-hydroxy-10-methoxy-3H-naphtho[2.1-b]pyrans as the primary product. These compounds are difficult to obtain pure due to their sensitivity to air. If the benzannulation reaction is performed...

متن کامل

Thermodynamic Parameters of Cis-Platin and Trans-Platin Complexes with Guanine in Water, A DFT Study

The binding energy and Thermodynamic Parameters of cis- Platinum Di Ammino Chlorine (cis-[Pt(NH3)2Cl]+) and trans- Platinum Di Ammino Chlorine (trans- [Pt(NH3)2Cl]+) complexes withGuanine has been studied by density functional theory (DFT) calculations in water. The bindingenergies (Ebin) of cis- and trans-[Pt(NH3)2ClG]+ are calculated to be 79.38 kcal/mol and 74.98kcal/mol, respectively. The b...

متن کامل

The Study of Electrochemical Behavior of Mono and Dinuclear Co(III) Complexes, trans-[pyCo((DO)(DOH)pn)(L)]PF6 and [{pyCo((DO)(DOH)pn)}2(μ-dicyd)](PF6)2

Electrochemical behavior of the new mono and dinuclear Co (III)  complexes of  the types trans-[pyCo((DO)(DOH)pn )(L)]PF6   and [{py Co((DO)(DOH)pn)}2 (μ-dicyd)] (PF6)2   have been studied in acetonitrile solution.  All the  mono nuclear complexes  show two quasi- reversible reduction couples associate  to Co(III/II)an...

متن کامل

Simultaneous and stereoselective construction of planar and axial centers of chirality.

Atropisomerism resulting from hindered rotation about single bonds can lead to molecules with centers of axial chirality and are widely used in asymmetric catalytic synthesis.1 Molecules containing planar centers of chirality have also been used as chiral ligands, particularly those containing η6-benzene and η5-cyclopentadienyl complexes.2 To our knowledge, there are no known synthetic methods ...

متن کامل

ذخیره در منابع من


  با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

عنوان ژورنال:
  • Journal of the American Chemical Society

دوره 127 49  شماره 

صفحات  -

تاریخ انتشار 2005