220366-02-9Relevant academic research and scientific papers
Allyltitanates in stereospecific additions to chiral σ-lactol: Efficient enantioselective route to a potential precursor of the C1-C9 portion of Tylonolide
Berque, Isabelle,Le Menez, Patrick,Razon, Patrick,Mahuteau, Jacqueline,Ferezou, Jean-Pierre,Pancrazi, Ange,Ardisson, Janick,Brion, Jean-Daniel
, p. 373 - 381 (1999)
The Hoppe reaction, which is an allylation reaction of aldehydes using an optically active titanated crotyl carbamate intermediate generated from the corresponding N,N-diisopropyl crotyl carbamate with n-BuLi/(-)-sparteine, was in most cases applied to achiral aldehydes. In this work an extension of this reaction is reported using a racemic γ-alkoxy allyltitanate (17) and an optically active aldehyde (16) to deliver in good yield the anti adduct 18 as the major isomer. When the corresponding σ-lactol 24 was used in place of aldehyde 16, the anti adduct 25 was obtained in 94% yield as the only product. Structural modifications effected on 25 delivered aldehyde 28 which was in turn submitted to a second allylation reaction in the presence of the optically active titanated crotyl carbamate 2, prepared as described by Hoppe from crotyl carbamate 1, to conduct to compound 29 in 80% yield. This derivative corresponds to a potential precursor of the C1-C9 portion of Tylonolide, aglycon of Tylosin (4).
