129245-36-9

Upstream product

• 603-35-0 triphenylphosphine 
• 87318-96-5 (4S)-4-((2R)-2-hydroxypent-4-enyl)-2,2-dimethyl-1,3-dioxolane 
• 188425-42-5 (S)-3-{(E)-(R)-6-[(2R,4S,6R,8R,9S)-4-(tert-Butyl-dimethyl-silanyloxy)-8-isopropyl-9-methyl-1,7-dioxa-spiro[5.5]undec-2-yl]-2,4-dimethyl-hex-4-enoyl}-4-isopropyl-oxazolidin-2-one 
• 115843-65-7 (2S,4R)-1-{2-[(3S,4R)-4-(tert-Butyl-dimethyl-silanyloxy)-3,5-dimethyl-hexyl]-[1,3]dithian-2-yl}-4-(2-trimethylsilanyl-ethoxymethoxy)-hept-6-en-2-ol 
• 115871-83-5 Toluene-4-sulfonic acid (2S,4R)-2-hydroxy-4-(2-trimethylsilanyl-ethoxymethoxy)-hept-6-enyl ester 
• 115843-76-0 {2-[(R)-1-((S)-2,2-Dimethyl-[1,3]dioxolan-4-ylmethyl)-but-3-enyloxymethoxy]-ethyl}-trimethyl-silane 
• 115843-63-5 Trimethyl-[2-((R)-1-(S)-1-oxiranylmethyl-but-3-enyloxymethoxy)-ethyl]-silane 
• 115843-77-1 (2S,4R)-4-(2-Trimethylsilanyl-ethoxymethoxy)-hept-6-ene-1,2-diol 
• 188476-98-4 (2R,4S,6R,8R,9S)-4-tert-Butyldimethylsilyloxy-9-methyl-8-isopropyl-2-prop-2-enyl-1,7-dioxaspiro<5.5>undecane 
• 115843-64-6 2-<(3S,4R)-4-tert-Butyldimethylsilyloxy-3,5-dimethylhexyl>-1,3-dithiane 
• 114047-95-9 (3S,4R)-4-tert-Butyldimethylsilyloxy-3,5-dimethylhex-1-ene 
• 114047-96-0 (3S,4R)-4-tert-Butyldimethylsilyloxy-3,5-dimethylhexanol 
• 114047-92-6 (2R,4S,6R,8R,9S)-4-Hydroxy-8-isopropyl-9-methyl-2-prop-2-enyl-1,7-dioxaspiro<5.5>undecane 
• 114047-97-1 (3S,4R)-4-tert-Butyldimethylsilyloxy-1-iodo-3,5-dimethylhexane 

Downstream Products

• 173327-01-0 C₅₂H₉₄O₁₁Si₃ 
• 135352-24-8 C₄₆H₈₂O₁₀Si₂ 
• 135415-62-2 6β-Hydroxy-3,4-dihydromilbemycin E 

Relevant academic research and scientific papers

Total synthesis of milbemycin E: Synthesis of the C(11)-C(25) fragment

Treatment of 2-methylpropanal with the (E)-but-2-enyl(diisopinocampheyl)borane 9 prepared from (+)-α-pinene gives the anti- and syn-products 10 and 11, ratio 88:12, from which the major anti-isomer 10 is separated by preparative GLC. Hydroboration-oxidation of its tert-butyldimethylsilyl ether 14 gives the primary alcohol 15 which has been converted into the bromide 16 and iodide 17. The propenyl(diisopinocampheyl)borane 23 prepared from (-)-α-pinene reacts with the aldehyde 22 prepared from (S)-malic acid to give the anti- and syn-1,3-diol derivatives 24 and 25, ratio 86:14, and the anti-product 24 has been taken through to the epoxide 31. Sequential alkylation of 1,3-dithiane with the iodide 17 and the epoxide 31 gives the 2,2-dialkyl-1,3-dithiane 33 which is converted into the spiroacetal 4 by treatment with dilute aqueous hydrogen fluoride. After protection, ozonolysis gives the aldehyde 43 which has been condensed with the ylide 34 to give the α,β-unsaturated ester 44. This has been reduced and converted into the iodide 46 which has been used to alkylate the chiral oxazolidinone 39 to give the required C(11)-C(25) fragment 48 of milbemycin E 1 after reductive removal of the chiral auxiliary. This has been converted into the phosphonium salt 2 ready for Wittig coupling with the hydroxybutenolide 3 for the assembly of the milbemycin nucleus.