213740-17-1

Upstream product

• 213740-15-9 (2R)-4-[1-(tert-butyl)-1,1-diphenylsilyl]oxy-2-methylbutan-1-ol 
• 410523-57-8 (2'S,2R)-(-)-1'-(4-tert-butyldiphenylsilyloxy-2-methyl-1-butylidenamino)-2'-(methoxymethyl)pyrrolidine 
• 410523-50-1 (S)-(-)-1'-(4-tert-butyldiphenylsilyloxy-1-butylidenamino)-2'-(methoxymethyl)pyrrolidine 
• 213740-16-0 ethyl (Z,4R)-6-[1-(tert-butyl)-1,1-diphenylsilyl]oxy-2-ethyl-4-methyl-2-hexenoate 
• 58479-61-1 tert-butylchlorodiphenylsilane 
• 126616-47-5 (R)-(-)-4-tert-butyldiphenylsilyloxy-1-methylbutanal 
• 2938-98-9 (R)-2-methylbutane-1,4-diol 
• 127793-62-8 4-((tert-butyldiphenylsilyl)oxy)butanal 
• 3641-51-8 2-(R)-methylsuccinic acid 
• 213740-06-8 (3Z,5R)-(-)-7-tert-butyldiphenylsilyloxy-3-hydroxymethyl-5-methylhept-3-ene 

Downstream Products

• 753016-54-5 tert-Butyl-[(4Z,6E)-(R)-5-ethyl-7-((2S,3S)-6-isopropoxy-3-methyl-3,6-dihydro-2H-pyran-2-yl)-3-methyl-hepta-4,6-dienyloxy]-diphenyl-silane 
• 410523-53-4 (2'R,6'R,1E,3Z,5R)-(+)-7-tert-butyldiphenylsilyloxy-1-(5',6'-dihydro-2'H-2'-isopropoxypyran-6'-yl)-3-ethyl-5-methylhepta-1,3-diene 

Relevant academic research and scientific papers

Asymmetric total synthesis of (-)-callystatin A employing the SAMP/RAMP hydrazone alkylation methodology

(equation presented) The asymmetric total synthesis of (-)-callystatin A has been achieved. The key steps generating the stereogenic centers rely on the asymmetric α-alkylation of aldehydes or ketones exploiting the SAMP/RAMP hydrazone alkylation methodology, as well as an enzymatic enantioselective reduction of a 3,5-dioxocarboxylate. For the construction of the alkene moieties, highly selective Wittig or Horner-Wadsworth-Emmons reactions were employed.

Oxabicyclo[3.2.1]oct-6-enes as templates for the stereoselective synthesis of polypropionates: Total synthesis of callystatin a and C19-epi-callystatin A

The total synthesis of the polyketide natural product callystatin A and its novel analog C19-epi-callystatin A is described. Our strategy features the use of an enantiomerically pure oxabicyclo[3.2.1]oct-6-ene as a template for the stereocontrolled preparation of the C15-C21 polypropionate region.

Asymmetric total synthesis of (-)-callystatin A and (-)-20-epi-callystatin A employing chemical and biological methods

An efficient asymmetric total synthesis of the potent cytotoxic marine natural product (-)-callystatin A and its 20-epi analogue has been achieved. The synthetic pathway involved the preparation of three fragments to be coupled with each other at the end of the route. The first fragment 3 was obtained using a biocatalytic enantioselective reduction of a 3,5-dioxocarboxylate as the key step. For the second intermediate 4 the asymmetric α-alkylation of an O-protected derivative of 4-hydroxybutanal was performed exploiting the SAMP/ RAMP hydrazone alkylation methodology, and followed by a highly Z-selective Homer-Wadsworth-Emmons reaction under modified conditions. For the synthesis of the polypropionate fragment 5 a diastereoselective syn-aldol reaction was employed between a chiral ethyl ketone and an α-substituted chiral aldehyde, both prepared in enantiopure form again by means of the asymmetric alkylation of their corresponding RAMP hydrazones. Finally, these three building blocks were coupled using highly E-selective Wittig reactions via allyltributylphosphonium ylides to afford the target compounds after a final oxidation/deprotection sequence.