conversions of 2-dia7ocamphane and P-diazonorbornane to tricyclene and nortricyclene, respectively. These results illustrate the differences in carbenic reactions of 6-membered rings in their chair and rigid-boat forms, Decomposition of diazocycloheptanes (Equation 1) yielded bicyclo[4.1.01heptane (1S%) by 1,3transannular insertion ar?d cycloheptene (82[2,j by 1,2-rearrangernent of hydrogen. Thermolysis of diazocyclooctane6(Equation 2) gave cis-bwyclo[3.3.0]octane (46%), bicyclo [.5.1 .Oloctane ( O C g j i and czs-cyclooctene (457,). Diazocyclononanea (Equation 3 ) yielded cis-hydrindsne (66%), bicyclo-
[6.1.0]nonaneg(10%), and cis-cyclononene (2276). Diazocy~lodecane~ (Equation 4) gave a greater variety of transannular reactions than its lower homologs: cis-bicyclo [5.3.0]decane (62Y0) and cis-decalin (187') l o result from transannular insertion and cis-cyclodecene ( I 45G) and transcyclodecene (6%) are formed by hydrogen rearrangement,
&
(3)
66";
apparent that bicyclic products are formed much inore efficiently by carbenic rather than cationic The absence of 1,4-inserinsertion p r o c e s s e ~ . ~ ~~~ tion products presumably stems from improper stereochemistry during decomposition of the medium-sized diazocycloalkanes. It is of interest that the insertion processes are stereoselective in that only cis-bicyclic hydrocarbons are formed. The extensive transannular insertion and the stereochemistry of decomposition of the diazoc>-rloalkanes thus parallel reactions of lithium diethylamide with cis-cyclodecene oxide and cisqdoiictene oxide to give cis-cis-I-decal01 and mido-c-is-bicyclo[5.3.0Idecan-2-01, and en&-cis-biCJ clo [3.3.O]octane-2-01, respectively, by processes involving simultaneous a-elimination and carbenic insertion. l 2 The stereospecific transannular insertions of carbenic systems to give cis-bicyclic derivatives is a necessary consequence of transfer of axial hydrogen in ring systems (Equation 512"-') and is consistent with the principle that carbenic insertions occur with retention in configuration. l i d
(11) Io base-catalyzed decomposition of CI-CIOcycloalkanone tosylhydrazones in protonic solvents, processes which a r e in p a r t cationic, the ratios of olefin t o bicyclic products are considerably greater thau those obtained from reactions under optimum carbenic conditions. ( 1 2 ) (a) A. C . Cope, G. A. Berchtold, P. E. Peterson and S. H. Sharman, J . Ain. Cheni. Soc., 83. M i 0 (1960). (b) Reactions of lithium diethylamide with lvanr-cyclodecene oxide and Irans-cyclocwtene oxide, presumably a-elimination carbenic processes, yield c i s : y a i i s I-decalol a n d exo-ris-bicyclo[3.R.O)ortan-2-ol, respectively: h C. Cope, hl Brown and H. H. Lee, ihid., 80, 2855 (1958),a n d A . C . Cope, H. H. Lee a n d H . E. Petree, i b i d . , 80, 2849 (1938). (13) (a) On the basis of stereochemical criteria, it is also expected t h a t t h e hicyclic products of kinetic control produced from transannular reactions of monocyclic derivntives via alkglatiim of the carbonium ion ty1.e or Iiy nucleophilic rlisnlacement will be of cisstructure. (b) FormolLsis of Irnm-cyclodecene oxide is reimrted t o yield frans-1-rlecalol, ni p. Y 9 O , a s a transannular produrt. D. J. C r a m in hl. S. Kernman's "Steric Effect? in Organic Chemistry," John Wiley and Sons, Inc., New York. N . Y , 195fi. p. 280 suggests t h a t t h e product is fvans-lrons-1-decalol. 7 h e present authors assign the structure of the transannular product a s us-cis-1-decalol, S W \!' Iflickrl, K Dannell, A. Gros? and 11 Nanb. A?t%.,602, 411 (1933), and ref. 11'. (c) T h e present authors wish t o acknorrledre the contributions of P B. Sarpeant, S Ranganathan, D C . Rerndt a n d s.-\'. I.ee t o these stereochemical conclusions.!"' (dl W,',,on E. Docring. 139th Meeting of t h e American Chemical Society, St. Louis, hlu March 30, 1961.
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CHEMISTRY
DEPARTMEYT
LESTERFRXEDIIAY
Carbenoid decomposition of C'I through CIO diazocycloalkanes is thus characterized by extensive 1,3-, 1,5- and 1,B-transannular insertion along with rearrangement of a-hydrogen. I t also is
Tim OHIO STATE UN~VERSITY HAROLD SIIECIITER C!ILLXBCS 10, OHIO RECEIVED JCSE 8, 1961
(7) Also prepared f r o m cycloheptene, methylene iodide a n d z i n c D (analytical sample) copper: b.p. 141.5-142O (700 m m . ) , W ~ ' 1.4601 (8) Essentially identical results have been obtained independently b y A. C Cope, M. Brown a n d G. L. Woo for decomposition cf p tosylhydrazones of cycloiictanone and cycloderanone and will be reported separately by them. A preliminary account of this work was given b y A . C. Cope in a lecture a t t h e Robert A Welch Fuundation Conferences on Chemical Research in Houston. Texas, November 7 ,
§ELECTIVE HYDROGENATION OF AN AROMATI: RING IN A NITRO COMPOUND'
1960. (9) Also synthesized from cis-cycluBctene, methylene iodide a n d zinc-copper: b.p. 43' (8 m m ) , n% l . l f i 2 2 (analytical sample). (IO) A s a t u r a t e d hydrocarbon alao was obtained (-l%,l which h a s bee0 assigned tentatively as bicyclo['i.l .O]decane.
Szr: IVe wish to report an instance of the selectivr hydrogenation of the benzene ring in s conlpouI1(1 (I) that also contaips a nitro group, the st.lect.ix-ity evidently resulting from a conibination of steric and electronic factors that protect the nitro groul) a n d facilitate attack on the xrornatic system. (1) Support nf this work by a grant (G-fi223) from the Xntionnl Srirnre Foundation is gratrfully ackn
