(S)-6-Methyl-∊-caprolactone

The chiral title compound, C7H12O2, a lactone derivative, features a seven-membered ring that adopts a chair conformation. The crystal structure is stabilized by weak C—H⋯O interactions occurring in the (100) plane. The absolute configuration was assigned on the basis of the enantioselective synthesis.

The chiral title compound, C 7 H 12 O 2 , a lactone derivative, features a seven-membered ring that adopts a chair conformation. The crystal structure is stabilized by weak C-HÁ Á ÁO interactions occurring in the (100) plane. The absolute configuration was assigned on the basis of the enantioselective synthesis.
The structure of (I) (Fig. 1) was solved in the non-centrosymmetric space group P2 1 with Z' = 1. The stereochemistry at the chiral center, C6, was assigned S based on the enantioselective synthesis of (S)-6-MeCL, which was reported to yield an enantiomeric excess greater than 99% (van As et al., 2007).
The crystal structure (I) is stabilized by weak C-H···O interactions (Table 1) with the four shortest contacts involving the O1 atom. These short contacts occur between molecules in the (1 0 0) plane, Fig. 2.

Experimental
Details about the synthesis of (S)-6-methyl-ε-caprolactone have been given in a previous paper (van As et al., 2007).

Refinement
In the absence of significant anomalous scattering effects, XXX Friedel pairs were merged prior to the refinement. The H atoms were found in difference Fourier maps and subsequently placed at calculated positions with C-H = 0.99-1.00 Å, and with U iso (H) = 1.2 or 1.5 times U eq (carrier C).   Refinement. Refinement of F 2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F 2 , conventional R-factors R are based on F, with F set to zero for negative F 2 . The threshold expression of F 2 > 2σ(F 2 ) is used only for calculating Rfactors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F 2 are statistically about twice as large as those based on F, and R-factors based on ALL data will be even larger.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å 2 )
x y z U iso */U eq O1