Enantioselective synthesis equipment

Experimental Procedure for the Enantioselective Synthesis of Tetrasubstituted Cyclopentane 9 An oven-dried vial (8 mL) equipped with a magnetic stir bar was charged with Pd2(dba)3-CHCl3 (10.4 mg, 0.01 mmol, 5 mol%) and l,2-bis(diphenylphoshino)ethane (dppe) (8.0 mg, 0.02 mmol, 10 mol%), fitted with... 

As one of the pioneering works on asymmetric synthesis, Evans and coworkers reported diastereoselective Diels-Alder reaction of acryloyl oxazolidinones mediated by Et2AlCl [140]. Intramolecular version of this cycloaddition was also reported, in which interesting stereochemical difference depending on substituents at oxazo-lidinone ring was found. As an another excellent example, Oppolzer and coworkers reported diastereoselective Diels-Alder reaction of chiral dienophiles equipped with camphorsultam auxiliary [141]. Recently, these diastereoselective reactions were applied to enantioselective synthesis of ceralure Bl, known as Mediterranean fruit fly attr actant (Scheme 6.118) [142]. 

Supercritical carbon dioxide represents an inexpensive, environmentally benign alternative to conventional solvents for chemical synthesis. In this chapter, we delineate the range of reactions for which supercritical CO2 represents a potentially viable replacement solvent based on solubility considerations and describe the reactors and associated equipment used to explore catalytic and other synthetic reactions in this medium. Three examples of homogeneous catalytic reactions in supercritical CC are presented the copolymerization of CO2 with epoxides, ruthenium>mediated phase transfer oxidation of olefins in a supercritical COa/aqueous system, and the catalyic asymmetric hydrogenation of enamides. The first two classes of reactions proceed in supercritical CO2, but no improvement in reactivity over conventional solvents was observed. Hythogenation reactions, however, exhibit enantioselectivities superior to conventional solvents for several substrates. 

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