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The absolute configurations of (-)-menthyl (-)-(S)-p-iodobenzenesulfinate and (-)-(R)-3-methylsulfinylpropylamine have been linked by a synthetic sequence involving an odd number of Grignard displacement reactions; consequently, this displacement has been rigorously shown to proceed with inversion of configuration at sulfur. This sequence, joined to present and earlier intercorrelations of sulfinates and sulfoxides, serves to establish absolute configurations in this series of compounds. The absolute configuration of (+)-methyl allyl sulfoxide, a key relay compound in the sequence, has been reassigned. Some apparent discrepancies which appeared in the earlier literature and which bear on the present work have been resolved.

the photoracemizations of 5 and 6 were studied. Irradiation of 0.5 X 10-3 M (-)-(R)-5 (eür 8800) in ether (Pyrex filter) for 2 min. resulted in 75 % decomposition. The recovered material was 57% racemized.The extraordinary photolability of 5 possibly results from facilitated carbon-sulfur bond fission through formation of a resonance-stabilized a-naphthylcarbinyl radical. In contrast, irradiation of 2 X 10-3 M (+)-(R)-615 (ed3oox 4600) in ether (Pyrex filter) for 1 hr. gave an 84% recovery of completely racemized12 6. This result provides striking evidence for the intramolecular sensitization process.Irradiation of (+)-(S)-methyl n-butyl sulfoxide10 ([a]25D +41.7°(isooctane), Xd¿01 222 µ, e 1110) for 10 min. (Vycor filter, cut-off below 220 µ) resulted in extensive decomposition. Undecomposed sulfoxide, recovered in 62% yield, had [cv]25d +41.6°(isooctane). Addition of naphthalene did not result in detectable racemization. It would thus appear that the arenesulfinyl chromophore10 is required for the photoracemization.

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