Conjugate addition of cyclohexanone lithium enolate to 2-nitro-2-butene and the Nef reaction on the resulting nitronate gave 2-(2-oxopropyl)cyclohexanone in good yield. Treatment of the 2-(2-oxopropyl)cyclohexanone thus obtained with potassium phosphate tribasic (K3PO4) in isopropanol gave 2, 3, 4, 5, 6, 7-hexahydro-3-methyl-3aH-inden-2-one (8). Application of the procedure to 1, 3-dimethyl-4-piperidone (11) gave the 1, 3, 4, 6, 7, 7a-hexahydro-6-oxo-2, 4, 7-trimethyl-2H-2-pyrindine (12). Epimerization of 12 with basic alumina gave (±)-tecomanine (1). The short synthesis of the alkaloid demonstrates the usefulness of K3PO4 as a base for cyclopentenone annulation of 1, 4-diketones without migration of the double bond.
Crosslink-cyclized cyclopentadiene and dihalobis type metal compound containing same as ligand
申请人:——
公开号:US20010012902A1
公开(公告)日:2001-08-09
A process for producing a crosslink-cyclized cyclopentadiene, comprising the steps of reacting a cyclopentenone with an alkali metal hydride to thereby reduce the cyclopentenone (reduction step A) into a cyclopentenol; and reacting the cyclopentenol with a dehydrating agent to thereby dehydrate the cyclopentenol (dehydration step B) into a crosslink-cyclized cyclopentadiene of the general formula (III):
1
wherein each of R
1
and R
2
independently represents a hydrogen atom or a linear or branched saturated alkyl group having 1 to 6 carbon atoms, n is an integer of 3 to 10, and the broken line in the 5-membered ring denotes that the 5-membered ring has two double bonds.
Process for the preparation of condensed cyclopentadiene derivatives, 1, 3 disubstituted derivatives and metallocene type compounds containing them as ligand
申请人:HONSHU CHEMICAL INDUSTRY CO. LTD.
公开号:EP1122229A1
公开(公告)日:2001-08-08
A process for producing a crosslink-cyclized cyclopentadiene, comprising the steps of reacting a cyclopentenone with an alkali metal hydride to thereby reduce the cyclopentenone (reduction step A) into a cyclopentenol; and reacting the cyclopentenol with a dehydrating agent to thereby dehydrate the cyclopentenol (dehydration step B) into a crosslink-cyclized cyclopentadiene of the general formula (III):
wherein each of R1 and R2 independently represents a hydrogen atom or a linear or branched saturated alkyl group having 1 to 6 carbon atoms, n is an integer of 3 to 10, and the broken line in the 5-membered ring denotes that the 5-membered ring has two double bonds.