Diastereoselective Complexation of Temporarily Chirally Modified Ligands: Enantioselective Preparation and Configurational Assignment of Synthetically Valuable η⁶‐Tricarbonylchromium‐1‐tetralone Derivatives

Abstract

L Am. Chem. Sor. 1987, 109, 203 -219. [14] For the metathesis of cis-2-pentene, the stereoselectivity at 0 % conversion is accurately determined by plotting the tronslcis ratio of 2-butene vs. the trans/cis ratio of 2-pentene and by extrapolating at truns/cis-2-pentene = 0 (in the case of trans-2-pentene, cisltrans C, is plotted vs. cisjtrans Cs)."51 1151 M. Leconte, J.-M. Basset, J. Am. Chem. Soc. 1979, 101, 7296-7302. [I61 The catalyst is deactivated by addition of benzaldehyde; palynorbornene is recovered after addition of THF to the reaction mixture, precipitation with methanol, filtration, and drying.[17] Dj.

Studies on the Synthesis of Vitamin D Analogs with Aromatic D-Ring

“…Complex 9 was prepared according to Schmalz's procedure (Figure 3) (Schmalz et al 1992). Reduction of ketone 6 with sodium borohydride in methanol provided alcohol 10 in 98% yield.…”

“…The solids were washed with CH 2 Cl 2 and the combined solution was concentrated in vacuo. The residue was purified by flash chromatography (50% CH 2 Cl 2 /hexanes) to give 11 (Schmalz et al 1992 …”

Ruthenium-catalyzed reduction of racemic tricarbonyl(η6-aryl ketone)chromium complexes using transfer hydrogenation: A simple alternative to the resolution of planar chiral organometallics

“…a chiral column after photochemical oxidation in air to release the ligand (R)-4a. The recovered and resolved ketone (R)-2a showed 82% ee, determined after reduction with sodium borohydride to (À)-syn-(S,R)-3a [13,15] followed by decomplexation and GC analysis on a chiral phase of the resultant (S)-4a (Scheme 1). A lower conversion (18%) was observed for the reduction of free 1-indanone (1a) to 1-indanol (R)-4a, with 96% ee (Table 2, entry 1).…”

“…Among the various procedures for the preparation of enantiopure planar chiral tricarbonyl(g 6 -arene)chromium complexes [11], organometallic aryl alcohols are obtained usually by complexation of racemic alcohols followed by fractionalization of their derivatives [12] or enzymatic resolution [8f,12b]. An efficient method to prepare such complexes of 1-tetralol derivatives consists of the direct diastereoselective coordination of the respective optically active alcohols to the tricarbonylchromium via Kü ndigÕs reagent, tricarbonyl(g 6 -naphthalene)chromium [13]. The oxidation of enantiomerically enriched (g 6 -aryl alcohol)Cr(CO) 3 organometallics is normally employed to generate chiral (g 6 -aryl ketone)Cr(CO) 3 compounds [12,13].…”

Efficient Enantioselective Syntheses of Sertraline, 2‐Epicatalponol and Catalponol from Tetralin‐1,4‐dione

“…[ 21] , and [Cr(CO) 3 (tetralone)] [22] were synthesized according to the cited literature procedures. 1,1,4,10,10-Hexamethyltriethylenetetramine was filtered on Al 2 O 3 and prenyl bromide was dried over CaH 2 and distilled prior to use.…”