The synthesis and reactivity of planar chiral 2-ferrocenyloxazolines and 1,1'bis (oxazolinyl) ferrocenes is reviewed, with particular emphasis on their applications in asymmetric catalysis.

--On treatment of N-tosylimines 1 and 4-hydroxyl-cis-butenyl arsonium salt 5 or sulfonium salt 11a with KOH in acetonitrile at room temperature, 2-(a-substituted N-tosylaminomethyl)-2,5-dihydrofurans 4 were obtained in moderate yields through a new ylide

A series of planar chiral 1,1A-P,N-2A-substituted ferrocene ligands 9-12 and 16, prepared with diastereopurity > 99+1, have been used to examine the role of planar chirality, and significant effects on enantioselectivity as well as the control of absolute configuration in palladium-catalyzed allylic alkylation as a model reaction were observed.

Alkylation under phase transfer conditions of the chiral glycine synthon 2 (prepared from the commercially available Oppolzer chiral sultam) with fluorinated analogues of 3,4-dimethoxybenzyl chloride proceeded with high diastereoselectivity. Hydrolysis of the Schiff base, removal of the chiral auxiliary and HBr demethylation produced 2-, 5-, 6-fluoro- and 2,6-difluoro-LDOPA in e.e. of >99%.

The spirolactam structure 1 reported in 1996 by Roggo et al. has been enantioselectively synthesized in 20 steps from (+)-Wieland-Miescher ketone. Spectra of this synthetic lactam differed from those of the natural spirolactam from the Roggo group, leading to the hypothesis that the natural lactammay be the regioisomer 27, a structure previously ascribed by Jarvis et al. to the natural product stachybotrylactam. This hypothesis was confirmed by the first total synthesis of (-)-stachybotrylactam (27). Double reductive amination of two molecules of aldehyde 29 with one molecule of L-lysine led by analogous chemistry to the first synthesis of the pseudosymmetric "dimer" 30, whose spectra corresponded to those of the natural "dimer" originally assigned structure 5 by the Roggo group.

The enantioselective total synthesis and structure revision of spirodihydrobenzofuranlactam 1 and of its regioisomer 25 are presented. Optically pure (+)-Wieland-Miescher ketone was utilized to construct the AB bicyclic core in 10 steps. Introduction of the resorcylate D-ring unit was achieved by use of our tert-butyl ester metalation sequence. Subsequent stereoselective spirocyclization to form the C-ring was followed by regioselective ring cyanation and lactam formation to produce the pentacyclic structure 1 and its regioisomer 25.

We review in this report the preparation of several side-chain fluorinated analogues of biologically important imidazoles and indoles. The building blocks used should also have applications in other synthetic problems. The addition of "FBr" to vinyl imidazole derivatives was used to prepare b-fluoro- and b,b-difluorohistamine and histidinols, as well as b-fluorourocanic acid. Deoxyfluorination of intermediate acylindoles was used to prepare a series of b,b-difluorotryptamine derivative, including the fluorinated analogue of the important neurotransmitter, serotonin.