Novel rearrangements of enynes catalyzed by PtCl2 [11]

Journal of the American Chemical Society

Volumn 122, Issue 28, 2000, Pages 6785-6786

  Fürstner, Alois ^a   Szillat, Hauke ^a   Stelzer, Frank ^a  

^a MAX PLANCK INSTITUT FÜR KOHLENFORSCHUNG   (Germany)

Author keywords

[No Author keywords available]

Indexed keywords

ALKADIENE; ALKYNE DERIVATIVE;

CATALYSIS; CHEMICAL STRUCTURE; ELECTRON TRANSPORT; ENZYME SUBSTRATE COMPLEX; LETTER; MOLECULAR INTERACTION; SYNTHESIS;

EID: 0038081446     PISSN: 00027863     EISSN: None     Source Type: Journal    
DOI: 10.1021/ja001034+     Document Type: Letter

References (16)

1. (a) Chatani, N.; Furukawa, N.; Sakurai, H.; Murai, S. Organometallics 1996, 15, 901.
2. (b) For similar reactions catalyzed by Ru catalysts see: Chatani, N.; Morimoto, T.; Muto, T.; Murai, S. J. Am. Chem. Soc. 1994, 116, 6049. (c) See also: Trost, B. M.; Chang, V. K. Synthesis 1993, 824.
3. (b) For similar reactions catalyzed by Ru catalysts see: Chatani, N.; Morimoto, T.; Muto, T.; Murai, S. J. Am. Chem. Soc. 1994, 116, 6049. (c) See also: Trost, B. M.; Chang, V. K. Synthesis 1993, 824.
4. Similar enyne metatheses catalyzed by palladol complexes have also been described. They are believed to proceed via a Pd(II)/Pd(IV) manifold involving palladacyclopentene and cyclobutene intermediates, cf.: (a) Trost, B. M.; Trost, M. K. J. Am. Chem. Soc. 1991, 113, 1850. (b) Trost, B. M.; Yanai, M.; Hoogsteen, K. J. Am. Chem. Soc. 1993, 115, 5294.
5. Similar enyne metatheses catalyzed by palladol complexes have also been described. They are believed to proceed via a Pd(II)/Pd(IV) manifold involving palladacyclopentene and cyclobutene intermediates, cf.: (a) Trost, B. M.; Trost, M. K. J. Am. Chem. Soc. 1991, 113, 1850. (b) Trost, B. M.; Yanai, M.; Hoogsteen, K. J. Am. Chem. Soc. 1993, 115, 5294.
6. Fernandez-Rivas, C.; Méndez, M.; Echavarren, A. M. J. Am. Chem. Soc. 2000, 122, 1221.
7. Chatani, N.; Kataoka, K.; Murai, S.; Furukawa, N.; Seki, Y. J. Am. Chem. Soc. 1998, 120, 9104.
8. Fürstner, A.; Szillat, H.; Gabor, B.; Mynott, R. J. Am. Chem. Soc. 1998, 120, 8305.
9. For the carbocation-like behavior of Pt(II)-alkyne complexes see: Chisholm, M. H.; Clark, H. C. Acc. Chem. Res. 1973, 6, 202.
10. Review: Mori, M. Top. Organomet. Chem. 1998, 1, 133.
11. 4 at 300 °C in vacuo was found to effect a very clean conversion into the desired product 4.
12. 4 was described for allyl propargyl ethers; in most cases, however, the yields obtained were rather low. Conversion of the alkyne into an allene followed by formation of a metallacycle was proposed as the reaction mechanism, cf.: Blum, J.; Beer-Kraft, H.; Badrieh, Y. J. Org. Chem. 1995, 60, 5567.
13. 2 were used.
14. One can envisage that intermediate B either evolves as indicated in Scheme 1 or converts into a cyclobutene derivative, which then undergoes an electrocyclic ring opening; note that both pathways deliver the same 1,3-diene product. If a cyclobutene is assumed as a discrete intermediate, the mechanism resembles the late steps of the mechanism proposed by Trost (ref 2), which differs conceptually from ours, however, in the assumed formation of a palladacycle as the triggering event.
15. Compounds 12, 14, 15, and 17 were obtained as pure (E)-isomers with respect to the configuration of the exocyclic double bond; in the case of product 19, however, the (Z)-isomer is formed as a byproduct (R = Me, E:Z = 10.3:1; R = H, E:Z = 2.4:1). The fact that (E,Z)-mixtures are obtained in these cases seems to rule out a concerted mechanism.
16. See also: Fürstner, A.; Voigtländer, D. Synthesis 2000, 959.