88536-77-0Relevant academic research and scientific papers
Comparison of the allylation reactions of aldehydes using allylstannanes with boron trifluoride etherate and boron trichloride
Marton, Daniele,Tagliavini, Giuseppe,Zordan, Michele,Wardell, James L.
, p. 127 - 138 (2007/10/02)
Reactions between allylstannanes, R2CH=CHCHR1SnBu3 (R1 = R2 = H (4); R1 = H, R2 = Me (5); R1R2 = (CH2)3 (6) and aldehydes, RCHO (e.g.R = Et) in the presence of BF3OEt2 in CH2Cl2 at -78 deg C produce stereoselectively erythro-RCH(OH)CHR2CH=CHR1 (with one equivalent RCHO) and 4-OH-3-R1-5-R2-2,6-R2-tetrahydropyrans (with an excess of RCHO).In contrast, when BCl3 is used in place of BF3OEt2 the reactions give mixtures of chlorinated alkenes (both homoallyl chlorides and allyl chlorides) and 4-Cl-3-R1-5-R2-2,6-R2-tetrahydropyrans (3; X = Cl).Thus 5, EtCHO and BCl3 (all equimolar) provide EtCHClCH2CH=CHMe (51percent, (E) + (Z)), EtCHClCHMeCH=CH2 (7percent, erythro + threo), EtCH2CH=CH-CHMeCl (30percent, (E) + (Z)) and 3 (12percent, X = Cl); with EtCHO (2.2 equivalents). 3 (X = Cl; cis/trans = 70/30) becomes the sole product.The product, erythro-EtCHClCHCH=CH(CH2)2CH2 (97percent) was produced from equimolar EtCHO, BCl3 and 6; with excess EtCHO (2.2 equivalents), 9-Cl-2,4-Et2-cis-3-oxabicyclononane (17percent; cis/trans = 45/55) and erythro-EtCHClCHCH=CH(CH2)2CH2 (78percent) were obtained.
Formation of homoallyl alcohols and 4-chlorotetrahydropyrans from allyl-stannanes, aldehydes and TiCl4 or Cp2TiCl2
Marton, Daniele,Tagliavini, Giuseppe,Zordan, Michele,Wardell, James L.
, p. 295 - 305 (2007/10/02)
Reaction between Bu3SnCHR1CH=CHR2 (1; R1 = H, R2 = H or Me; R1, R2 = (CH2)3) and EtCHO in the presence of TiCl4 or Cp2TiCl2 are reported.The compound, Cp2TiCl2, has been found to be an effective Lewis acid catalyst for the allylation of EtCHO using 1 (R1 = H, R2 = Me) and 1 (R1, R2 = (CH2)3) in CH2Cl2 or Et2O solutions at -78 deg C; the products after hydrolysis are homoallyl alcohols with stereo- and regio-selectivities different from those found for TiCl4- reactions.Reactions with an excess of EtCHO in the presence of TiCl4 give 4-Cl-3-R1-5-R2-2,6-2Et-tetrahydropyrans (2) via insertions of a second EtCHO into the metal-O bond of the initially produced homoallyl alcoholate: the trans-2 compounds are obtained from threo-EtCH(OM')CHR2CH=CHR1 and cis-2 from erythro-EtCH(OM')CHR2CH=CHR1 (e.g., M' = TiCl3).
