extracted with EtOAc (3 X 100 mL) and with ether (3 X 100 mL). The organic extracts were combined, washed with saturated NaCl and with water, dried over MgS04, and concentrated. The dark residue (1.3 g) was chromatographed over silica gel. The fractions eluted with CC14-CH2C12 (1:1) gave 500 mg of syrup (12.4%) which showed a strong band at 1715 cm"1 in the IR. The NMR (CDCI3) displayed signals at 8. 05-7.3 (m, 4 H), 3.85 (s, 2 H), and 2.21 ppm (s, 3 H). Crystallization from CHCl3-hexanes yielded 70 mg of 14: mp 77-78 °C; mass spectrum, m/e 216 (M+), 173, 154,133; NMR (CDClg) 8.0 (d, J = 8 Hz, 2 H), 7.5 (d, J = 8Hz, 2 H), 3.85 (s, 2 ), 2.21 (s, 3 H). The mother liquor after filtration of these crystals showed NMR and mass spectra very similar to those of the original syrup, indicating a mixture of 12 and 13. In another experiment 2.5 g of phenylacetone in 5 mL of FSO3H was stirred at room temperature for 1.75 h and added dropwise to a mixture of 75 mL of CHCI3 and ice. The aqueous phase was extracted again with 75 mL of CHC13, and the combined organic extracts were washed with saturated NaCl solution (3 x 150 mL), dried over MgS04, filtered, and concentrated to yield 1.75 g of a light brown oil. The NMR disclosed that 50% of the starting material remained. The mixture was treated again with 5 mL of FS03H at room temperature for 20 h, yielding 1.70 g of crude product in which the starting material was absent (by NMR). After two recrystallizations from CCU-CHCI3 and three from EtOH, 60 mg of 13 was obtained; mp 75.5-76 °C. Anal.

The regio-and stereoselectivity of phenylselenenyl chloride additions to allylic alcohols and their derivatives have been systematically studied. On the basis of the results, a mechanism involving two basic premises is proposed. These are as follows: (a) allylic oxygen's direct selenonium ion formation to the syn face of the double bond; (b) axial attack of the chloride ion is kinetically favored over equatorial attack. A series of rules which are useful for predicting the regio-and stereoselectivity of phenylselenenyl chloride additions to allylic systems are discussed. In addition, these reactions can be used as the key step in a general 1,3-enone transposition sequence. Several examples of this transposition sequence are illustrated.The synthetic utility of olefin addition reactions involving electrophilic selenium species is now well estab-li~hed.~" Recently, we reported that (a) phenylselenenyl chloride adds to allylic alcohols in a highly regio-and stereoselective fashion and that (b) additions of this type could be used as the key step of a simple 1,3-enone transposition ~equence.~ In this paper we provide insight into the origins of the regio-and stereoselectivity of these addition reactions as well as further demonstrate the generality of the transposition sequence.The results of our study involving the regio-and stereochemical consequences of phenylselenenyl chloride additions to allylic alcohols and their derivatives are given below. Most of the adducts listed were characterized on the basis of their NMR spectra. By use of this method of analysis, unequivocal assignment of the regio-and stereochemistry of most of the phenylselenenyl chloride adducts could be readily achieved.PhSeCl Additions to Allylic Alcohols and Their Derivatives Terminal allylic alcohols are quite unique in their reactions with phenylselenenyl chloride (1). Just as in the reaction of simple terminal olefins with 1, terminal allylic alcohols react with lZase under kinetic conditions (-78 "C, CH2C12) to provide anti-Markovnikov adducts and under thermodynamic conditions (25 "C, CHCl, or CH,CN) to produce Markovnikov adducts. If the anti-Markovnikov adduds which are formed under kinetic conditions are not quickly made to undergo a subsequent reaction at low temperature (e.g., oxidative elimination, dehydrohalogenation, etc.), they begin to isomerize to their corresponding Markovnikov adducts. These processes are illustrated below in the reaction of 1 with 2a and 2b. (1) Fellow of the Alfred P. Sloan Foundation, 1980-1984. Recipient of a Camille and Henry Dreyfus Teacher-Scholar Fellowship, 1981-1986. (2) For additions of simple selenium electrophiles to double bonds, see: (a) Liotta, D.; Zima, G. Mannafov, T. G.; Berdnikov, K. A.; Kamarovskaya, 0. A. Zh. Org. Khim 1973, 9, 1983. (3) For the use of selenium electrophiles in the confunctionalization of double bonds, see: (a) Clive, D. L. J.; Chittattu, G.Additions of 1 to nonterminal, acyclic allylic alcohols usually result in the formation of a mixture of regioisomers. For example, add...

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