Chiral Recognition of Alcohols in the Crystal Lattice of Simple Metal Complexes ofO,O′-Dibenzoyltartaric Acid: Enantiocomplementarity and Simultaneous Resolution

Abstract

A simple preparative method for the enantiomeric enrichment of alcohols is reported. Crystallization of the complexes of alcohols formed with calcium and zinc O,O'-dibenzoyltartrates led to effective resolutions of the alcohols. However, zinc and calcium dibenzoyltartrates are complementary resolving agents upon coordinative resolution of less-hindered alkoxy alcohols. Mixed copper(ii) salts of O,O'-dibenzoyltartaric acid formed with carboxylic acids can also be applied to the resolution of alkoxy alcohols, thereby providing the simultaneous resolution of an alcohol and a carboxylic acid. Zinc dibenzoyltartrate can form coordination compounds with alkoxy alcohols as well as lattice inclusion compounds with simple alcohols as revealed by the four X-ray structures reported here.

Optical Resolution of Dimethyl α-Hydroxy-Arylmethylphosphonates via Diastereomer Complex Formation Using Calcium Hydrogen O,O′-Dibenzoyl-(2R,3R)-Tartrate; X-Ray Analysis of the Complexes and Products

“…Earlier, we were successful in the optical resolution of a series of cyclic phosphine oxides and phosphinates using the acidic calcium salt of O,O'-dibenzoyl-(2R,3R)-tartaric acid as the resolving agent [32]. It was successfully used for the resolution of tertiary phosphine oxides [33,34], α-alkoxyalcohols [35], α-alkoxycarboxylic acids [36], as well as α-and βhydroxycarboxylic esters [37] and the biologically active Tenofovir Alafenamide [38].…”

Strategies in optical resolution: a practical guide

“…In fact, tetrahydrofurfuryl alcohol can be resolved with the calcium salt of 2 functioning as a coordinative complexing agent. 21 The phospholene oxides 30 can be resolved with 6 and also with spiro 6 analogue 31 via molecular complexes, its resolution with Ca salts of 2 and 3 is feasible via coordinative complexes. It is advantageous if the resolving agent is a well-known, often used reagent, but any structural similarity with one of the enantiomers of the racemate may also be an important aspect.…”

Resolution of Enantiomers by Non-Conventional Methods

“…From ethanol, it is the complex of the R-alcohol [(±)-FuOH•(R,R)-DBTA 2-Ca 2+ ] that preferentially crystallizes. 39 The very charm of this procedure is that the complex itself can serve as a resolving agent, and was used for the resolution of tetrahydrofurfuryl carboxylic acids [(±)-FuAc] (Scheme 25). It should be reasonable to assume that after the termination of crystallization during a resolution procedure, the composition of the precipitate remains constant; however, there are some exceptions.…”