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COMMUNICATIONS enantiomeric efficiencies of this method are fully comparable to those of the enzymatic procedure. 4) This method can provide highly vcrsatilc cyclohexenone chiral synthons very efficiently. 5 ) The reaction mechanism has been proven to include a suprafacial 1.3-hydrogen migration pathway. E.uprrinzcntal ProcedureTranzforiiiatioii o i 6 c into 5b. To a stirred solution of 6 c (405 mg. 1.0 mmol) in I,?-dichloroetliane (4.6 mL) was added [Rh:(S)-hinap)(cod)]ClO~ (18.6 mg. 19.9 inniol) i n 1 .Z-dichloroethane (0.5 mL) dropwise at room temperature under argon ;ind the niiytiire w'as relluxed for 17 11. The solvent was evaporated. the residue dissolved 111 T H F ( 5 mL). and the resulting solution stirred with nBu,NF ( I 0 M in 7 IfF, 1 0 inl,) at 0 ' C for 5 min. The solution was diluted with ether and washed succeaiwly with water and brine. dried over MgSO,. and concentrated under reduced pressure. The residue was chromatographed on silica gel (EtOAc: hexanc 1.9) to gi%e 5b a s colorless crystals (276 mg, 94.9%) (96.1 % LT). A single recrystallmition from hexane give the optically pure material (99.5 "/ o ee) as colorless prism\. m p 32 C. [r];' = -27.0 ((, = 1.08 in CHCI,).

Physical laws underlying the intravascular magnetic guidance of a novel drug carrier are discussed. The drug carrier is a magnetically responsive drug-bearing microsphere measuring approximately 1 μm in diameter. The microspheres consist of an albumin matrix in which a prototype drug (adriamycin HCl) and ultrafine Fe3O4 particles are entrapped. An in vitro analog of the human circulatory system is used to test both bipolar and unipolar magnetic arrangements which can retain microspheres flowing in aqueous suspension in the area of applied magnetic field. Retention of the microspheres by the magnetic field is shown to vary with the linear velocity of the viscous suspending medium and to be dependent on the magnitude of the applied magnetic force. This system permits extracorporeal control over the distribution of intravascular soluble chemotherapeutic agents and allows their concentration at specified body sites.