471 Heteroatom Chemistry Volume 9, Number 5, 1998 Chiral Recognition of Selenides and Iodides by 1 H NMR Spectroscopy in the Presence of a Chiral Dirhodium Complex Shahid Hameed, 1 Roshan Ahmad, 1 and Helmut Duddeck 2 1 Quaid-I-Azams University, Department of Chemistry, Islamabad, Pakistan 2 Universita ¨t Hannover, Institut fu ¨r Organische Chemie, Schneiderberg 1B, D-30167 Hannover, Germany Received 15 October 1997 SCHEME 1 ABSTRACT: Chiral recognition of aryl alkyl selenides and alkyl iodides can be achieved by 1 H NMR spec- troscopy in the presence of dirhodium tetra-(R)- or tetra-(S)--methoxy--(trifluoromethyl)-phenyl- acetate [Rh 2 (MTPA) 4 , 1]. Generally, these classes of compounds are weak donors and fail when using the classical chiral lanthanoid shift reagent. Alkyl bro- mides do not show similar effects.  1998 John Wiley & Sons, Inc. Heteroatom Chem 9:471–474, 1998 RESULTS AND DISCUSSION Parallel to the rapid development of stereoselective organic syntheses, chiral recognition is becoming in- creasingly important. Among these techniques, spec- troscopic and chromatographic methods are most prominent [1]. NMR spectroscopy, in particular 1 H NMR, is well established because it often gives good results when spectra are recorded in the presence of a chiral lanthanoid shift reagent (CLSR) [2]. How- ever, this method requires a substrate with a suffi- ciently basic functional group such as OH, NR 2 , and others. If these are absent, complexa- C  O, tion between substrate and CLSR molecules is too weak for chiral recognition. Thus, there is a consid- erable demand for certain classes of compounds to Correspondence to Helmut Duddeck, E-mail: duddeck@mbox. oci.uni-hannover.de.  1998 John Wiley & Sons, Inc. CCC 1042-7163/98/050471-04 have an alternative procedure. Recently, we have shown that (R)-1 (Scheme 1) and its enantiomer (S)-1 (dirhodium complexes with four MTPA, i.e., Mosher’s acid [3], residues) are very suitable for chi- ral recognition in various classes of compounds that form complexes with CLSR being too weak for chiral recognition by 1 H NMR spectroscopy. Among those functional groups are olefins [4], epoxides [5], and nitriles [6]. This article reports that our method can even be extended to selenides and iodides. Organoselenium chemistry plays an increasing role in modern stereo- and regioselective organic chemistry [7], and, in parallel, 77 Se NMR spectros- copy has been developed into a routine method [8]. Therefore, it is useful to have an independent tech- nique to monitor the composition of mixtures of en- antiomers of aryl alkyl selenides. Therefore, we