(1R,2S)-methyl 1-((1R,2R,5R)-5-(tert-butyldiphenylsilyloxy)-2-(hex-5-enyl(methyl)carbamoyl)cyclohexanecarboxamido)-2-vinylcyclopropanecarboxylate → (1aR,3aR,5R,7aR,15aS,Z)-methyl 5-(tert-butyldiphenylsilyloxy)-9-methyl-3,8-dioxo-1a,2,3,3a,4,5,6,7,7a,8,9,10,11,12,13,15a-hexadecahydro-1H-benzo[c]cyclopropa[g][1,6]diazacyclotetradecine-1a-carboxylate

Participants

Reaction Steps

To a solution of compound 41 (0.74 mmol) in dichloroethane (700 mL), degassed for 45 min by bubbling nitrogen, was Zhan 1B (4%, 22 mg) at 80° C. under continuous degassing with nitrogen. After the reaction was refluxed for 1 hr, a second portion of Zhan 1B (22 mg) was added. After heating for 1.5 hr, the reaction mixture was cooled down to room temperature, poured onto a silica pad, and eluted with DCM. The crude material was purified by chromatography on silica gel (DCM/MeOH) to yield compound 42 as a brown solid in 81% yield. MS (ESI, EI+): m/z=617 (MH+).

Provenance & Evidence