A new palladium-catalyzed oxidative cyclization process leading to the functionalized bicyclo[4,3,0]nonenes is serendipitously discovered during attempts to form aza-heterocycle by the amino-Heck reaction of trans-2-vinylclohexyl phosphinyloxime. Under the influence of Pd(dba)2/Et3N/1:1 N2-O2 (1:1, v/v) (Method A) or Pd(OAc)2/Et3N/O2 (Method B), the reactions afford the substituted cis-1-hydroxyl-8-formyl-bicyclo[4,3,0]non-8(9)-enes or bicycle[4,3,0]non-1(9)-en-8-ones in varying yields with the incorporation of molecular oxygen into the structures. The 5,6-bicyclic scaffold of these products is presumably derived from tandem double intramolecular cyclization followed by the ring-opening of an aza-palladium(II) tricyclic intermediate.

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Under the catalysis of Cu(OTf)2 in refluxing CH2Cl2, ethyl α‐dizao α‐(diethylphosphoryl)acetate was shown to undergo a new cyclization reaction to afford a pentacovalent oxaphosphirane product. The reaction is proposed to occur through the addition of the P=O double bond to the copper carbenoid, followed by the hydrolysis of the ylide intermediate. Our finding represents the first example on producing oxaphosphiranes from dizao phosphoryl compounds. On the other hand, the corresponding rhodium carbenoid displayed the different reactivity under the same thermal conditions, to produce the β‐propiolactone through the well‐recognized C‐H insertion pathway.

Access to Functionalized Bicyclo[4,3,0]nonenes via Palladium-Catalyzed Oxidative Cyclization of 2-Allylcyclohexyl Oximes. -Starting from the chiral title substrates the synthesis of either bicyclic hydroxyaldehydes or enones bearing aliphatic substituents can be achieved by variation of the catalytic system. -(ZHU*, J.-L.; WU, S.-T.; SHIE, J.-Y.; J. Org. Chem. 79 (2014) 8, 3623-3633, http://dx.doi.org/10.1021/jo5005422 ; Dep. Chem., Natl. Dong Hwa Univ., Shoufeng, Hualien 974, Taiwan; Eng.) -B. Voigt 45-108

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