Trimethylsilyldiazomethane → [2-(3-Ethynyl-cyclohex-3-enyl)ethoxy]-triisopropyl-silane

Participants

Reaction Steps

A solution of TMS-diazomethane (4.61 mL, 9.22 mmol) in THF (60 mL) was reacted with n-BuLi (5.0 mL, 7.99 mmol) at −78 EC for 0.5 h. 5-(2-triisopropylsilanyloxy-ethyl)-cyclohex-1-enecarbaldehyde (Intermediate R13) was added via cannula. The mixture was reacted at −78 EC for 1 h and at 0 EC for 1 h. After work-up and chromatographic purification, [2-(3-ethynyl-cyclohex-3-enyl)-ethoxy]-triisopropyl-silane (Intermediate R14) was isolated, 1.44 g (77%). To Intermediate R14 in THF (70 mL) at 0 EC was injected tetrabutyl ammonium fluoride (TBAF). After 2 h at rt the mixture was subjected to an aqueous work-up. The material was purified by chromatography to give the alcohol, 2-(3-ethynyl-cyclohex-3-enyl)-ethanol 0.68 g, (98%). The alcohol was oxidized by a Swern reaction to the aldehyde stage and aldehyde was subjected to the applicable step of Method A to yield 4-(3-ethynyl-cyclohex-3-enylmethyl)-1H-imidazole (Intermediate R15).

Provenance & Evidence