Treatment of the allene-ene-yne substrates with [{RhCl(CO)2}2] effected the intramolecular [2+2+2]-type ring-closing reaction to produce various of tri- and tetracyclic derivatives containing a cyclopropane ring. The reaction is highly stereoselective as well as stereospecific with good to excellent yields.

Treatment of dodecatrienyne derivatives with [RhCl(CO) ] in refluxing toluene effected the cycloisomerization to produce tricyclo[6.4.0.0 ]dodecadienes. The one-carbon shortened undecatrienyne derivatives, however, afforded bicyclo[6.3.0]undecatriene derivatives instead of tricyclic compounds, the latter of which are well known as a basic skeleton of naturally occurring octanoids. On the basis of two experiments with deuterated substrates, a plausible reaction mechanism for the construction of these products was proposed.

A novel Rh(I)‐catalyzed intramolecular [2 + 2 +2] cycloaddition of allene‐ene‐ynes yields cyclopropane‐fused polycyclic products.

Stereospecific and Stereoselective Rhodium(I)-Catalyzed Intramolecular [2 + 2 + 2] Cycloaddition of Allene-Ene-Ynes: Construction of Bicyclo[4.1.0]heptenes. -A novel Rh(I)-catalyzed intramolecular [2 + 2 +2] cycloaddition of allene-ene-ynes yields cyclopropane-fused polycyclic products. -(OHTA, Y.; YASUDA, S.; YOKOGAWA, Y.; KUROKAWA, K.; MUKAI*, C.; Angew. Chem., Int. Ed. 54 (2015) 4, 1240-1244, http://dx.doi.org/10.1002/anie.201409155 ; Div. Pharm. Sci., Grad. Sch. Med. Sci., Kanazawa Univ., Kanazawa 920-11, Japan; Eng.) -Mais 25-127