Preparation of α-substituted γ-alkoxyallylstannanes from β-tributylstannyl acrolein acetals: scope of the method and primary rationalization of the obtained results
alpha-Substituted gamma-alkoxyallylstannanes were obtained from beta-tributylstannyl acrolein acetals when reacted with lower order magnesium cyanocuprates in the presence of boron trifluoride at low temperature. In the case of n-alkylcyanocuprates an anti S(N)2' substitution on a cisoid conformation appears to be the main reaction pathway. However, subtle competitions with other mechanisms may occur depending on the experimental conditions, on the reagents or on the substrates. These drawbacks constitute limitations for the use of the method especially when enantioenriched alpha-substituted gamma-alkoxyallylstannanes are desired. (C) 2004 Elsevier B.V. All rights reserved.
<i>Z</i>- and<i>threo</i>-Selective 1-Methyl-2-butenylation of Aldehydes by 4-(Tributylstannyl)-2-pentene
作者:Hideyoshi Miyake、Kimiaki Yamamura
DOI:10.1246/cl.1994.587
日期:1994.3
Transmetallation of an E,Z-mixture of 4-(tributylstannyl)-2-pentene with BuSnCl3 proceeded stereoselectively to give (E)-4-(butyldichlorostannyl)-2-pentene (3). The subsequent addition of it to an aldehyde proceeded Z- and threo-selectively to give 1-methyl-2-butenylated product.
Pd(0) Catalyzed Hydrostannation of Conjugated Dienes. A Facile and Highly Regio- and Stereoselective Synthesis of (<i>Z</i>)-2-Alkenylstannanes
作者:Hideyoshi Miyake、Kimiaki Yamamura
DOI:10.1246/cl.1992.507
日期:1992.3
Tetrakis(triphenylphosphine)palladium(0) catalyzes the hydrostannation of conjugateddienes. The reaction proceeds highly regio- and stereoselectively to give (Z)-2-alkenyltributylstannanes. This m...