203174-67-8Relevant articles and documents
Approaching the C33-C38 fragments of amphotericin B and nystatin by a retro-[1,4]-Brook rearrangement and the stereoselective manipulation of the resulting allylsilane
Gibson, Christoph,Buck, Thomas,Walker, Martina,Brückner, Reinhard
, p. 201 - 205 (2007/10/03)
Sulfide S-4 (98.6% ee) furnished allylsilane S,S-anti-2 through a potassium naphthalenide induced, highly stereoselective retro-Brook rearrangement. Treatment with diethylborane followed by NaOOH/H2O2 delivered alcohol 9 as a single diastereomer. Cylization (→10), oxidation (→16), and methylation gave ketone 17. Reduction of 17 with Et3SiH in CF3CO2H was accompanied by an unprecedented rearrangement of the neighboring oxasilolane ring to the C-silylated tetrahydropyran 20. It was oxidized to alcohol 21 which - if one inverted its OH group - would become a new C33-C38 building block for the polyol/polyene antibiotics amphotericin B and nystatin.