Stability of regioisomeric sugar allyltins. Cleavage of the carbon oxygen bond under radical conditions
摘要:
Secondary sugar allyltin derivatives [Sug-CH(SnBu3)-CH=CH2] decompose at high temperature (140 degreesC) with elimination of the tin moiety and opening of the sugar ring. The cis-dienoaldehydes thus formed react with Ph3P=CH-CO2Me to afford the corresponding trienes, which spontaneously undergo stereoselective intramolecular [4+2] cycloaddition to optically pure, highly oxygenated bicyclo[4.3.0]nonene derivatives. Primary sugar allyltins [Sug-CH=CHCH2-SnBu3] are thermally stable and do not decompose up to 170 degreesC. (C) 2001 Elsevier Science Ltd. All rights reserved.