PREPARATION OF 3,3-BIS(TRIBUTYLSTANNYL)PROPENES, POTENTIAL NEW 1,3-ALLYL DIANIONS

ldimethyl)silyloxy-3,3-bis(tributylstannyl)propene 11 as well as propy lcarbamoyloxy-3,3-bis(tributylstannyl)propene 10 have been prepared up on addition of Bu3Sn(Bu)Cu(CN)Li-2 8 to diverse gamma-heterosubstitute d 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 se quence where the stannylated acrolein B is thought to be a common inte rmediate. The best results were obtained upon single conjugate additio n of 8 to (E)-3-(tributylstannyl)-2-propenal 12 (78%). A two-pot synth esis of the title compound was developed from the inexpensive malonald ehyde bis(dimethyl)acetal 14. (C) 1997 Elsevier Science Ltd.