COM M U N ICATlONS
can assume that the ee value is very high in this reaction, since the 100MHz 13C NMR spectrum of (S,S,R)-8 (R = Ph) shows signals from only one diastereoisomer.
We can therefore access interesting synthetic building blocks in high optical yield using this new method of asymmetric C-C bond formation. In this way the principle of diastereoselective complexation of a temporarily chirally modified ligand"] is used for enantioselective preparation of the chiral q2-enonemanganese complex 5, from which, after diastereoselective conversion and decomplexation, chiral, nonracemic, synthetically useful products can be obtained. Further investigations are currently underway, which focus predominantly on the use of functionalized alkylating reagents, as well as reactions at the car-bony1 group of the planar-chiral enone-metal complex.
Experimental Procedure
(R)-7 (R = alIy1)-n-Butyllithiuin (515 pL, 0.77 mmol, 1 . 5 ~ in hexane) was added dropwise to a solution of diisopropylamine (101 pL. 0 77 mmol) in T H F ( 5 mL) at 0 -C. The resulting solution was stirred for 30 min at 0 C This LDA solution was then added dropwise over a period of IOmin to a solution of (S)-5 (150mg. 0.55 mmol) in T H F ( 5 mL), precooled to -78 C. After addition, the solution was stirred for 2 h at -78 ' C . Finally allyl bromide (67 pL, 0.77 mmolj was added, and the solution allowed to warm to 0 C over a period of about 12 h. The reaction mixture was concentrated on a rotary evaporator, and the components separated by flash chromatography with diethyl ether as eluent. Yield-70mg of (S,R)-6, yellow powder ( YO). [ T I ; ' = -103 (c = 1 0 in benzene); 'H NMR (400 MHz, C,D,): 6 = 5.65 (br., 1 H). 4.93 (ZH), 3.91 (1 H), 3.73-3.67 (4H), 3.30 (1 H), (lOOMHz,C,D,:* = quatenaryc. + = CH,, -= CH,CH,j:d = 233.6(*),232 7 (-), 67.3 (-), 53.9 ( -) . 4 0 8 (-), 34.8 ( + I . 33.7 ( + I , 12.1 ( -) . IR (KBr)i. = 1965 (s). 1904(s), 1699(s), 1457 (w). 1175