_P.-Powell-auth.-Principles-of-Organometallic-Chemistry-Springer-Netherlands-1988

Allyl and diene complexes
derivative. This rapidly adds to the diene affording a methylenecyclopentane.
Although there is no direct evidence for the trimethylenemethanepalladium
intermedia te, a stable osmium complex has been isolated from the reaction of the
precursor with Os(C0) 2 (PPh 3 ) 3 • If cyclic alkenes are used, fused ring systems are
formed. The reaction has been used in the synthesis of several complex organic
molecules including loganin, a key intermediate in the biosynthesis of alkaloids.
/,Os"'
oc' J PPh3
co
Me 3Si)=
+ -
AcO
w
=COA< + (
SiMe 3
Pdln
(R=Hl
S02 Ph
(Z=C02 Et, COR,CN,S02 R)
OR OH
Five-membered rings are present, for example, in the physiologically important
prostanoids as well as in monoterpenes, the iridoids, in the antibiotic hirsutic acid
and in nepetalactone, an essential oil from catmint.
8.3 References
Băckvall, J.E. (1983) Palladium in some selective oxidation reactions. Ace. Chem. Res., 16,
335.
Billington, D.C. (1985) '1'-Allyl-nickel halides as selective reagents in organic synthesis.
Chem. Soc. Revs., 14, 93.
Efraty, A. (1977) Cyclobutadiene complexes. Chem. Rev., 77, 691.
Erker, G .. Kriiger, C. and Miiller, G. (198 5) '1 4 -Conjugated diene zirconocene and
hafnocene complexes. Adv. Organomet. Chem., 24, 1.
Jolly, P.W. (1985) '1'-Allylpalladium complexes. Angew. Chem. (Int. Edn), 24, 283.
Jolly, P.W. and Mynott, R. (1981) 13 C n.m.r. of organotransition metal complexes. Adv.
Organomet. Chem., 19, 257.
Trost, B.M. (1986) 3 + 2 cycloaddition approaches to 5-membered rings. Angew. Chem.
(Int. Edn), 25, 1.
Trost, B.M. (1986) Transition metals and olefins- a promising land; a personal account.].
Organomet. Chem., 300, 263.
Yasuda, H., Tatsumi, K. and Nakamura, A. (1985) Early transition metal diene complexes.
Ace. Chem. Res., 18, 120.
Problems
1. Comment on each of the following.
(a) Diallylmercury gives an n.m.r. spectrum with 1 H resonances giving three
groups of peaks at different chemical shifts with an intensity ratio of 2: 1 : 2 at all
272