Preparation of 3,3-bis(tributylstannyl)propenes, potential new 1,3-allyl dianions

Article abstract of DOI:10.1016/S0040-4039(97)01558-X

(E)-1-(tert-Butyldimethyl)silyloxy-3,3-bis(tributylstannyl)propene 11 as well as 1-N,N-diisopropylcarbamoyloxy-3,3-bis(tributylstannyl)propene 10 have been prepared upon addition of Bu₃Sn(Bu)Cu(CN)Li₂ 8 to diverse γ-heterosubstituted acrolein precursors, followed by addition of excess HMPA and of the required electrophile. A E/Z ratio of 95:5 was reached in the case of 11. The reaction may occur through an addition-elimination-addition sequence where the stannylated acrolein B is thought to be a common intermediate. The best results were obtained upon single conjugate addition of 8 to (E)-3-(tributylstannyl)-2-propenal 12 (78%). A two-pot synthesis of the title compound was developed from the inexpensive malonaldehyde bis(dimethyl)acetal 14.