Metal carbonyl-promoted rearrangement of cyclopropenes to naphthols
作者:M. F. Semmelhack、Suzzy Ho、Michael Steigerwald、M. C. Lee
DOI:10.1021/ja00248a047
日期:1987.7
Metal-Catalyzed Cyclopropene Rearrangements for Benzannulation: Evaluation of an Anthraquinone Synthesis Pathway and Reevaluation of the Parallel Approach via Carbene-Chromium Complexes
作者:M. F. Semmelhack、Suzzy Ho、D. Cohen、M. Steigerwald、M. C. Lee、G. Lee、Adam M. Gilbert、William D. Wulff、Richard G. Ball
DOI:10.1021/ja00095a014
日期:1994.8
The reaction of 3-arylcyclopropenes with Cr(CO)(6) and Mo(CO)(6) produces naphthols, in an example of metal-promoted benzannulation. Substituents at C-3 (in addition to aryl) have a strong effect on the success of the process: 3-H derivatives are generally effective, but the yields decrease for 3-alkyl derivatives as the size of the alkyl group increases. The 3,3-diphenyl and 3-cyano derivatives are unreactive. The mechanism is postulated to involve metal-complexed vinyl carbene units, parallel with the benzannulation reaction involving arylcarbene complexes with alkynes. The regioselectivity has been probed with various unsymmetrically 1,2-disubstituted 3-arylcyclopropenes. The results suggest a simple correlation with steric size, consistent with initial cleavage of the cyclopropene sigma bond bearing the smaller substituent. The result of this regioselectivity is a product structure showing a substituent arrangement opposite to that from the carbene-chromium approach; the smaller substituent of the cyclopropyl double bond ends up adjacent to the phenol OH in the product. Catalytic activity at low efficiency was observed, using a Mo(CO)a catalyst. However, the use of Mo(CO)(6) also promotes formation of indenes as significant byproducts at the expense of naphthalenes. Attempts to use the arylcyclopropene rearrangement to convert a 3-(1,4-dimethoxy-2-naphthyl)cyclopropene to an anthraquinone skeleton produced instead a phenanthrene via an unusual substitution for a methoxy substituent. A related example previously reported to produce anthraquinones via the naphthylcarbene-chromium/ alkyne reaction was shown to be in error; the correct structure is again a phenanthrone, and the product is exactly parallel with that observed in the cyclopropene rearrangement. A naphthoquinone substituted with a cyclopropene at C-2 does provide the first example of metal-promoted benzannulation to give an anthraquinone.
MIURA, MASAHIRO;NOJIMA, MASATOMO;KUSABAYASHI, SHIGEKAZU;MCCULLOUGH, K. J., J. AMER. CHEM. SOC., 1984, 106, N 10, 2932-2936
作者:MIURA, MASAHIRO、NOJIMA, MASATOMO、KUSABAYASHI, SHIGEKAZU、MCCULLOUGH, K. J.
DOI:——
日期:——
Ozonolysis of a series of 1-substituted indenes. The substituent steric effects on the ozonide exo/endo ratios
作者:Masahiro Miura、Masatomo Nojima、Shigekazu Kusabayashi、Kevin J. McCullough
DOI:10.1021/ja00322a032
日期:1984.5
Ozonolyse d'une serie d'indenes disubstitues (-1,2 et -1,3) et trisubstitues (-1,2,3) dans CCl 4
Ozonolyse d'une serie d'indenes dissubstitues (-1,2 et -1,3) et trisubstitues (-1,2,3) dans CCl 4