(S,S)-2-allyl-2-chloro-3,4-dimethyl-5-phenyl-[1,3,2]oxazasilolidine → (R)-N'-(1-tert-butyl-but-3-enyl)-hydrazinecarboxylic acid benzyl ester

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Reaction Steps

Briefly, benzyl carbazate (compound A) was reacted with pivaldehyde to give (E)-N′-(2,2-dimethyl-propylidene)-hydrazinecarboxylic acid benzyl ester (compound B). Compound B was reacted with (S,S)-2-allyl-2-chloro-3,4-dimethyl-5-phenyl-[1,3,2]oxazasilolidine (Compound C; see Leighton et al., J. Am. Chem. Soc. 125:9596 (2003) and WO 03/074534) to give (R)—N′-(1-tert-butyl-but-3-enyl)-hydrazinecarboxylic acid benzyl ester (compound D). Compound D was reacted with 3,5-dimethyl benzoyl chloride to give (R)—N′-(1-tert-butyl-but-3-enyl)-N′-(3,5-dimethyl-benzoyl)-hydrazinecarboxylic acid benzyl ester (compound B). Compound E was hydrogenated to give (R)-3,5-dimethyl-benzoic acid N-(1-tert-butyl-butyl)-hydrazide (compound F). Compound F was reacted with 2-ethyl-3-methoxybenzoyl chloride to give Compound 1. The crude material was triturated first with ether (2% ethanol) and then with 1:1 hexanes:ether in a fritted glass Büchner funnel. The product was then washed with deionized water with thorough mixing and allowed to dry in air. Compound 1 was isolated as a white powder.

Provenance & Evidence