The stereoselective synthesis of functionalized vicinal diamine systems by the double allylation reactions of “protected” 1,2-bis-imine precursors.

The Chemistry of Vicinal Diamines

“…By employing the bisimine (R,R)-375, prepared from commercially available (R)-a-methylbenzylamine (282), a 6:1 ratio of the two syn diastereomers was obtained, the major isomer being tentatively assigned as 376, which was then converted into enantiomerically pure C 2 -symmetric diamine 377 (Scheme 91). [163] Reactions of the same bisimine (or its enantiomer) with other organometallic reagents have since been reported; they also proceed with syn selectivity, but with opposite stereochemical outcomes. Savoia et al [164] obtained the diamine 378 as the major isomer from the reaction of (S,S)-375 with allylzinc bromide in THF, and adduct 379 was mainly obtained by Simpkins et al [165] from the reaction of (R,R)-375 with phenylmagnesium chloride in diethyl ether (Scheme 91).…”

A New Efficient Synthesis of (R,R)-2,2′-Bipyrrolidine: An Interesting Chiral 1,2-Diamine withC2 Symmetry

“…[6] We have developed an alternative shorter strategy, which is feasible on a large scale (no chromatographic purifications are required). The first steps are based on the chiral diamine synthesis reported by Neumann et al, [7] latterly improved by Savoia and co-workers, [8] which starts from N,N-bis[(S)-1-phenylethyl]ethanediimine (5; Scheme 2). [9] O O N N By this method, N,N-bis[(S)-1-phenylethyl]-(R,R)-4,5-diamino-1,7-octadiene (6) is obtained in good yield (60 %) and excellent diastereoselectivity (> 99 %) when isolated and purified.…”

New Fluorescent Calix Crown Ethers, Part II: Synthesis and Complex Formation in Solution and the Solid State

“…Some non-hydrogenation methods for the removal of a diphenylmethane group as protecting group for an amine are reported. [13][14][15][16] diphenylmethane-protected crown ether 6 to allow for easier removal without an adverse effect to the coumarin double bond. Unfortunately, none of the reported methods worked properly in our hands.…”