CAS Registry numbers: ( l ) , 62139-73-5; (2), 62139-14-6; ( 3 a ) , 62139-75-7: (3b), 62139-76-8; (3c), 62139-77-9; ( 3 d ) , 62182-97-2; ( 4 a ) . 62139-78-0; (4h), 62139-79-1; ( 4 c ) , 62139-80-4: (4d),62139-56-4: ( 5 ) , 54008-64-9: (6),62139-57-5; ( 7 ) . 62139-586; ( 8 ) . 2954-84-9: ( 9 1 , 62139-59-7; (Me3Si)2CBrZ,29955-10-0; PhMe&iCI, 768-33-2; Ph2P(0)OAg, 621 39-60-0; (PhO)PhP(O)OAg, 621 39-61-1: (PhO),P(O)OAg, 22350-95-4; Tos. OAg, 16836-95-6; 2,3-dimethylbutadiene, 51 3-81-5; Me3Si-N=N-SiMe3, 13436-03-8 Unsaturated Silicon Compounds, Part 1. Also Part 40 of Compounds of Silicon and its Group Homologs.-Part 39: N. Wiberg, G. Hiihler, 2. Naturforsch. 8 3 1 , 1317 (1976). W Scklenk. J . Renning, Justus Liebigs Ann. Chem. 394, 221 (1912); cf. also: F . S . Kipping, J . Chem. SOC.1927, 104. N . S. Nanzetkin, V. M . Vdocin, L. E. Gusei'nikoc, V. I. Zuc'xilolj. Izv. Akad. Nauk SSSR Ser. Khim. 1966.584; f.E. Gusel'ntkov, M . C . Flowers, Chem. Commun. 1967, 864. a ) L . E. Gusel'nikot, N. S. Namefkin, I! M . Klocin, Acc. Chem. Res. 8, 18 (1975): and references cited therein; h) A. G . Brook, J . W Harris, J. Am. Chem. Soc. 98, 3381 (1976); H . Sakurai et a/., ibid. 98, 7453 (1976): 0 . L . Chapman et a/., ibid. 98, 7844 (1976); M . Ishikawa, 7: Furhikami, M . Kimiadn, J. Organomet. Chem. 118, 139, 155 ( 1 976); c) C . M. Golini, R. D . Birsh, L . H . Sommer, J. Am. Chem. SOC. 97, 7371 (1975); and references cited therein. N. Wiberg, Angew. Chem. 83, 379 (1971); Angew. Chem. Tnt. Ed. Engl. 10, 374 (1971). N . Wiherg, H . J . Praehr, J. Organomet. Chem. 40, 289 (1972); and references cited therein. Apart from ( 1 1) the products include, inter a h , bis(trimethylsily1)diazomethane (MesSi)ZC=N=N which is also accessible ria other routes; cf. D. Selferth, Th. C . Flood, J. Organomet. Chem. 29, C25 (1971). D. Sejferth. R. f. Lamberth j r . , E. M . Hanson, J. Organomet. Chem. 24, 647 ( 1970). Note added in proof(Apri1 6, 1977): As an example of a carbonyl compound, henzophenone reacts with ( 1 ) t o form a [2+2] cycloadduct decomposing above about 80°C.

[I]

[2] [3]

141

[5]

161 [7]

[El [9]

Absolute Configuration of the Cancerostatic S( - )-Cyclophosphamide By Dorota A . Adamaik, Ryszard Kinas, WolJram Saenger, and Wojciech J . Stec[*l Cyclophosphamide (Cytoxan, Endoxan, NSC 26271 ; N , N bis(2-chloroethyl)tetrahydro-2H-l,3,2-oxazaphosphorin-2amine 2-oxide) ( 1 ) is a clinically tested cancerostatic"]. The observation that patients treated with racemic ( * ) - ( I ) preferentially excreted (-)-(f )[*] led to synthesis of the two enantiomersT31. Experiments on mice showed ( - ) - ( I ) to have a therapeutic index LD50/ID90towards ADJ/PC6 plasma cell tumor t h a t is twice as high as that of the (+)-enantiomerT4]. These fiirdings prompted us to carry out the present crystal structure analysis in order to elucidate structure-function relations. (-)-(f ) crystallizes from CC14 as irregular stout crystals of space group PI with a=10.500(4), b=10.490(4), c=10.761(4)A, c~=110.0(2),8=110.0(2), ./=108.9(2)"; Z=3. 2635 X-ray reflections were recorded with a four-circle diffractometer (Cu-K, radiation, 2 e/w scan) and corrected for geometric factors. The structure could be solved by direct methods after determination of the normalized structure amplitudes Ehkrand refined in the usual way. The coordinates and temperature factors were varied both for the model ( x , y , z ) and for the enantiomorph ( X , j , T ) taking account of the anomalous [*] Priv.-Doz. Dr. W. Saenger, Dr. D. A. Adamiak Abteilung Chemie, Max-Planck-Institut fur Experimentelle Medizin Hermann-Rein-Strasse 3, D-3400 Gottingen (Germany) Dr. R. Kinas, Doz. Dr. W. J. Stec (Centre of Molecular and Macromolecular Studies, Polish Academy of Sciences Boczna 6,90-362 Lodz (Poland)

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scattering of P and C1. Final weighted discrepancy indices (R,= [h(lF&l- IFcalcl)2/C~IFobslZ]1'2 are 7.28 % for ( x , y , z ) and 6.77 % for (X,jj,,23. On the basis of Handton's R factor test['], the model ( x , y , z )could be ruled out with a reliability index of