ALLYLSTANNATION .10. STEREOCHEMICAL COURSE OF THE ADDITION-REACTIONS OF (E/Z)-BU3SNCH2CH=CHCH3 WITH ALDEHYDES IN THE PRESENCE OF LEWIS-ACIDS (BU2SNCL2, BF3.ET2O, AND TICL4)

Reactions between (E/Z)-Bu3SnCH2CHCHCH3 and RCHO (R  CH3, C2H5, n-C3H7, n-C4H9, n-C5H11, (CH3)2CH, (CH3)3C, C6H5, CH2CH, CH2C(CH3), (E)-CH3CHCH, (E)-C3H7CHCH, (E)-C6H5CHCH) have been carried out in the presence of Lewis acids such as Bu2SnCl2, BF3·Et2O and TiCl4. The stereochemical course of the reactions to give homoallylic alcohols does not necessarily depend on the formation of intermediate Lewis acid-aldehyde complexes, but rather upon the formation of allylmetal compounds (e.g., Bu2ClSnCH2CHCHCH3, Bu2ClSnCH(CH3)CHCH2, Cl3TiCH2CHCHCH3, etc.) which are the actual species which react with the carbonyl compounds. Bu3SnCH2CHCHCH3 does not undergo the reaction.