1,3-bis(phenylmercapto)propane and 1-chloro-3-(phenylmercapto)propane: useful precursors for 1,3-dilithiopropane synthons in the preparation of 1,5-diols

Treatment of 1,3-bis(phenylmercapto)propane (1) with an excess of lithium a nd a catalytic amount of DTBB (3.5 mol%) at -78 degrees C followed by react ion with a carbonyl compound [(BuCHO)-Bu-t, PhCHO, (PhCH2)(2)CO, Et2CO, (CH 2)(5)CO, (CH2)(7)CO, (-)-menthone, Ph2CO] leads, after hydrolysis with wate r, to symmetrically substituted 1,5-diols (2). Starting from 1-chloro-3-(ph enylmercapto)propane (3) and by successive treatment with: (a) lithium-naph thalene at -78 degrees C; (b) a carbonyl compound {Me2CO, (CH2)(5)CO, (CH2) (7)CO, (-)-menthone, [CH3(CH2)(4)](2)CO} at the same temperature; (c) lithi um powder at -50 degrees C; and (d) a second carbonyl compound [(BuCHO)-Bu- t, PhCHO] at the same temperature and final hydrolysis with water yields un symmetrically substituted 1,5-diols (4). (C) 2000 Elsevier Science Ltd. All rights reserved.