An investigation of the behaviour of α,β-unsaturated sulfoxides in the presence of trimethylsilyl iodide
摘要:
A mild, efficient and seemingly general method for converting alpha,beta-unsaturated sulfoxides into carbonyl compounds by means of trimethylsilyl iodide (TMSI) is described. Experiments on different substrates and trimethylsilyl halides lead to the conclusion that the oxidation state of the sulfur atom, on one hand, and halogen kind in TMSX on the other, assume a determining role in the progression of the reaction. The ease of experimental procedure, the possibility of H-1 NMR monitoring, and good yields of final products constitute advantages of the TMSI-promoted conversion of alpha,beta-unsaturated sulfoxides into carbonyl compounds. (C) 2002 Elsevier Science Ltd. All rights reserved.
First hetero-diels-alder reaction of an enantiopure 2-sulfinylbuta-1, 3-diene: mild and effective stereocontrolled synthesis of pyranoid derivatives
摘要:
LiClO4 catalyzed cycloaddition of (R-s,E)-3-[(1S)-isoborneol-10-sulfinyl]-1-methoxybuta-1,3-diene 1 with ethyl glyoxalate occurred with good endo and facial diastereoselectivities to give (2R,6S,R-S)-6-ethoxycarbonyl-4-[(1S)-isoborneol-10-sulfinyl]-2-methoxy-5,6-dihydro-2H-pyran 2 as the main product, easily isolated as crystalline material in high yield. (C) 1997 Elsevier Science Ltd.