240417-69-0Relevant academic research and scientific papers
Enantioselective total synthesis of epothilones A and B using multifunctional asymmetric catalysis
Sawada, Daisuke,Kanai, Motomu,Shibasaki, Masakatsu
, p. 10521 - 10532 (2007/10/03)
An enantioselective total synthesis of epothilones A (1) and B (2) using multifunctional asymmetric catalysis such as a cyanosilylation of an aldehyde, an aldol reaction of an unmodified ketone with an aldehyde, and a protonation in the conjugate addition of a thiol to an α,β-unsaturated thioester has been achieved. We divided 1 and 2 into fragment A, fragment B, and fragment C. A catalytic asymmetric synthesis of fragments A and B was accomplished using a catalytic asymmetric cyanosilylation as a key step. An enantiocontrolled synthesis of fragment C was achieved in two ways. One is the use of a direct catalytic asymmetric aldol reaction of an unmodified ketone with an aldehyde as a key step, and the other utilizes a catalytic asymmetric protonation in the conjugate addition of a thiol to an α,β-unsaturated thioester as a key step. Suzuki cross-coupling of fragment A with fragment C followed by Yamaguchi lactonization as key steps led to an enantiocontrolled synthesis of epothilone A (1). On the other hand, Suzuki cross-coupling of fragment B with fragment C followed by Yamaguchi lactonization accomplished an enantiocontrolled synthesis of epothilone B (2).
