142791-16-0

Upstream product

• 71098-88-9 N-phenylselanylphthalimide 
• 142791-09-1 ent-19-hydroxygibberella-2,16-diene 
• 4968-37-0 gibberellin A₁₄ dimethyl ester 
• 38290-45-8 ent-gibberella-2,16-diene-7,19-dioic acid 7,19-dimethyl ester 
• 55093-77-1 C₂₀H₃₀O₂ 
• 142791-08-0 ent-19-methylsulfonyloxygibberella-2,16-diene 
• 142791-07-9 ent-5,19-dimethylsulfonyloxygibberella-2,16-diene 

Relevant academic research and scientific papers

Preparation of ent-Gibberellane and 16-epi-ent-Gibberellane

A mixture of ent-gibberellane 1 and 16-epi-ent-gibberellane 2, the parent hydrocarbons of the gibberellin plant hormones, has been prepared from gibberellin A14 dimethyl ester 5 by deoxygenation sequentially at carbons 3, 7 and 19 and then hydrogenation.The most direct route proceeded by dehydration of the 3-ol in 5 to the 2-ene 27, hydride reduction to the 7,19-diol 28, hydride reduction of the corresponding 7,19-dimethanesulfonate 29 to the 19-monomethanesulfonate 30, and then hydrolysis to the 19-ol 31 which was converted into the phenyl selenide 38.Hydrogenolysis of the selenide 38, with concomitant hydrogenation of the 2- and 16-double bonds, gave a mixture of ent-gibberellane 1 and 16-epi-ent-gibberellane 2 in the ratio of 73:27.This mixture was separated on the analytical scale by capillary GLC and the two epimers were characterised by GLC-MS to provide reference mass spectra and KRI as fossil markers.The structures 1 and 2 were assigned on the basis that the major component was the endo-16-methyl epimer.