236390-89-9

Upstream product

• 236390-87-7 (Z)-(2R,3R,4S)-1-(tert-Butyl-dimethyl-silanyloxy)-7-(4-methoxy-benzyloxy)-2,4-dimethyl-hept-5-en-3-ol 
• 1026364-57-7 Carbonic acid tert-butyl ester (Z)-(1R,2S)-1-[(R)-2-(tert-butyl-dimethyl-silanyloxy)-1-methyl-ethyl]-5-(4-methoxy-benzyloxy)-2-methyl-pent-3-enyl ester 
• 236390-86-6 (2R,3R,4S)-1-(tert-Butyl-dimethyl-silanyloxy)-7-(4-methoxy-benzyloxy)-2,4-dimethyl-hept-5-yn-3-ol 

Downstream Products

• 236390-91-3 tert-Butyl-{(2R,3S,4R)-4-[(2R,3S)-3-(4-methoxy-benzyloxymethyl)-oxiranyl]-3-methoxymethoxy-2-methyl-pentyloxy}-dimethyl-silane 
• 236390-90-2 (2R,3S,4R)-1-(tert-Butyl-dimethyl-silanyloxy)-4-[(2R,3S)-3-(4-methoxy-benzyloxymethyl)-oxiranyl]-2-methyl-pentan-3-ol 

Relevant academic research and scientific papers

Synthesis of a syn,syn,syn,syn-stereopentad precursor of the marine sponge polyketide callystatin A

A C13-22 syn,syn,syn,syn-stereopentad precursor of the cytotoxic polyketide callystatin A has been prepared. The synthesis involved BF3- promoted addition of the (M)-allenylstannane 28 to the α-methyl-β-OTBS aldehyde 8 to afford the syn,syn adduct homopropargylic alcohol 29. Protection as the cyclic anisylidene acetal 31 and reduction of the acetylenic triple bond with Red-Al gave the (E)-allylic alcohol 32. This was subjected to Sharpless asymmetric epoxidation and subsequent treatment with an ethylcopper reagent to yield diol 34; hydrogenolysis of the derived tosylate 37 with LiBEt3H afforded 38. Acetal hydrogenolysis with DIBAl-H and oxidation yielded aldehyde 40 which was subjected to Horner-Emmons homologation to afford ester 41. This ester was converted to ester 44, an intermediate in the Kobayashi synthesis, with which it was found to be identical.