An efficient route leading to the functionalized five-membered cyclic sulfinate esters (y-sultines) 14a,b and 21a,b is described on the basis of the reaction of the N-protected cystinol derivatives 11 and 20, respectively, with N-chlorosuccinimide (NCS) and AcOH. Ring-opening reactions of the sultines can be performed in two ways. Treatment of 14 with Clz or NCS/HCl gives the sulfonyl chloride 15 by cleavage of the C-O bond. Selective cleavage of the S-OR bond occurs when 14 or 21 is treated with MeSCH2Li, n-BuLi, or C,H,C(Li)(H)CN to yield the hydroxyalkyl sulfoxides 22-26. These nucleophilic ring-opening reactions are stereospecific and proceed with inversion at the sulfoxide sulfur atom. The synthesis of 23a constitutes a new approach to the antibiotic sparsomycin (1). Circular dichroism measurements can be employed in the assignment of absolute configurations to the sulfoxide sulfur atom of the sultines 14a,b and 21a,b (patents pending).

(S)-cyclohexylglycine (1) is prepared in high yield by hydrogenation of (S)-phenylglycine (2) using rhodium on carbon as the catalyst. Cyclohexylglycine (α-amino-cyclohexaneacetic acid) (1) is used as a nonnatural amino acid in pharmaceutical studies and in peptide chemistry. 1 Apart from its close analogy to phenylglycine (2), it functions as a structural mimic of the natural amino acids valine and isoleucine. 2 In connection with the synthesis of non-natural amino acids, we were looking for a method to prepare multigram quantities of (S)-1.

The crystal and molecular structures of racemic (DL) N‐acetyl‐N‐hydroxyvaline and 2‐(N‐acetyl‐N‐hydroxyamino)butyric acid have been determined from three‐dimensional X‐ray data. The crystals of both compounds are monoclinic, space group P21/a. The molecular conformation of these amino acid derivatives is similar, as far as the Φ torsion angle is concerned, but the ψ values are significantly different. In the crystal structures of both compounds, two series of intermolecular hydrogen bonds (HB's) are present: NOH…O  COH HB's link the N‐hydroxy and carboxylic groups, while OCOH…OCN HB's link the carboxylic and N‐hydroxyamidic groups.

Die Cystein‐Derivate (IIa) werden nach Reduktion zu den Alkoholen (IIb) durch Umsetzung mit N‐Chlorsuccinimid (NCS) in Essigsäure in die Sultine (III) übergeführt.

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