Author(s): Mark J. Ford;Julian G. Knight;Steven V. Ley;Sadie Vile
Abstract: Oleandrose (I, R = R1 = H)(II) was prepd. in 8 steps from (S)-Me3CSiMe2OCHMeCHO via cyclic sulfites III (4 isomers) and the key intermediate p-allyl tricarbonyl iron complexes IV and V. Acetylation of II gave an equimolar mixt. of diacetate I (R = R1 = Ac) and monoacetate I (R = Ac, R1 = H) (VI). The diacetate was selectively deacetylated with LiBEt3H to give monoacetate I (R = H, R1 = Ac), which was coupled via its imidazolylcarbonyl deriv., with VI to give the bis-oleandrose fragment VII. VII was selectively deacetylated with LiBEt3H, treated with thiocarbonyldiimidazole and then coupled with avermectin B1a aglycon monoacetate in the presence of AgClO4 and K2CO3 to give avermectin B1a diacetate. The latter compd. was deacetylated with excess LiBEt3H to give avermectin B1a. [on SciFinder (R)]
Notes: CAN 114:82316 33-4 Carbohydrates Dep. Chem.,Imp. Coll. Sci., Technol. Med.,London,UK. Journal 0936-5214 written in English. 1826-67-1 (Vinyl magnesium bromide) Role: RCT (Reactant), RACT (Reactant or reagent) (Grignard reaction of, with silyloxypropanal); 87727-28-4 Role: RCT (Reactant), RACT (Reactant or reagent) (Grignard reaction of, with vinylmagnesium bromide); 132039-55-5P Role: SPN (Synthetic preparation), PREP (Preparation) (prepn. and Michael addn. of, with methanol); 13089-77-5P (L-Oleandrose) Role: RCT (Reactant), SPN (Synthetic preparation), PREP (Preparation), RACT (Reactant or reagent) (prepn. and acetylation of); 132039-56-6P; 132039-57-7P Role: RCT (Reactant), SPN (Synthetic preparation), PREP (Preparation), RACT (Reactant or reagent) (prepn. and coupling of, with oleandrosyl acetate); 71826-88-5P Role: RCT (Reactant), SPN (Synthetic preparation), PREP (Preparation), RACT (Reactant or reagent) (prepn. and deacetylation of); 132039-52-2P; 132055-83-5P Role: RCT (Reactant), SPN (Synthetic preparation), PREP (Preparation), RACT (Reactant or reagent) (prepn. and desilylation of); 93338-33-1P Role: RCT (Reactant), SPN (Synthetic preparation), PREP (Preparation), RACT (Reactant or reagent) (prepn. and epoxidn. of); 72595-80-3P; 72599-12-3P Role: RCT (Reactant), SPN (Synthetic preparation), PREP (Preparation), RACT (Reactant or reagent) (prepn. and exhaustive carbonylation of); 132039-59-9P Role: RCT (Reactant), SPN (Synthetic preparation), PREP (Preparation), RACT (Reactant or reagent) (prepn. and glycosidation by, of avermectin B1a aglycon monoacetate); 132055-85-7P Role: RCT (Reactant), SPN (Synthetic preparation), PREP (Preparation), RACT (Reactant or reagent) (prepn. and glycosidation of, with oleandrosyloleandrose deriv.); 132077-25-9P; 132077-26-0P; 132077-27-1P; 132077-28-2P Role: RCT (Reactant), SPN (Synthetic preparation), PREP (Preparation), RACT (Reactant or reagent) (prepn. and reaction of, with nonacarbonyldiiron); 132055-84-6P Role: RCT (Reactant), SPN (Synthetic preparation), PREP (Preparation), RACT (Reactant or reagent) (prepn. and reaction of, with thiocarbonyldiimidazole); 132039-53-3P; 132039-54-4P Role: RCT (Reactant), SPN (Synthetic preparation), PREP (Preparation), RACT (Reactant or reagent) (prepn. and reaction of, with thionyl chloride, cyclic sulfites by); 72777-93-6P Role: RCT (Reactant), SPN (Synthetic preparation), PREP (Preparation), RACT (Reactant or reagent) (prepn. and redn. of, with DIBAL-H); 132039-58-8P; 132077-29-3P Role: RCT (Reactant), SPN (Synthetic preparation), PREP (Preparation), RACT (Reactant or reagent) (prepn. and regioselective deacetylation of, with lithium triethylborohydride); 106564-92-5P Role: SPN (Synthetic preparation), PREP (Preparation) (prepn. of); 65195-55-3P (Avermectin B1a) Role: SPN (Synthetic preparation), PREP (Preparation) (prepn. of, by glycosidation of aglycon with oleandrosyloleandrose deriv.)
Keywords: avermectin B1a; oleandrose; oleandrosyloleandrose prepn coupling avermectin B1a aglycon
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Dr Julian Knight
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