the layers were separated. The aqueous layer was neutralized with sodium bicarbonate and extracted with three 50-mi portions of ether. The combined ether extracts were concentrated at reduced pressure on the steam bath.18 If the residue contained a mixture of solid and an oil, it was washed with 10 ml of cold (0°) methanol and filtered immediately. If a solid was not (18) Conveniently, crystallization was found to be hastened if the ether extracts were not dried before removal of excess solvents, especially when p-methoxyaryl isoxazoles were synthesized.Kovacs, Mayers, Johnson, Cover, and Ghatak formed, 5-10 ml of methanol was added and crystallization occurred upon refrigeration of the mixture. Recrystallization was effected with ethanol or benzene (see Table I).

No abstract

A highly regioselective 8-endo-trig-aryl radical cyclisation of the vinylcyclohexanols 2a-c and allylcyclohexanols 6a-c with tri-n-butyltin hydride provides decahydrodibenzo-[a,e]-and -[a,dl-cyclooctenols 3a-c and 7a-c respectively, in moderate to good yields.

No abstract

A simple convergent and general method has been developed for the synthesis of (f)-isopisiferin (1 c), a rearranged abietane diterpene, having a hexahydrodibenzo[a,d]cycloheptene ring system, and the related model systems (la) and (lb), through the respective enolisable tricyclic ketone mixtures (12c) and (13c), (12a) and (13a), and (12b) and (13b), obtained from the corresponding easily accessible 2-arylethyl-3,3-dimethylcyclohexanones (7c), (7a), and (7b). Demethylation of the styrenoid ethers (15b) and (15c) under acid conditions gave the tetracyclic dienones (17b) and (17c) through Ar,-5 cyclisation.The recent structural elucidation 'J of isopisiferin (lc), pisiferanol (2), and a number of related compounds, isolated from the seeds of Chamaecyparis pisifera (Cupressaceae), along with the earlier reported phenols, pisiferin (34) and barbatusol (3b),5 represent an interesting group of rearranged 9(1& 20)-abeo-abieta-8,11,13-triene diterpenoids. Recently, the total syntheses of ( + )-pisiferin (3a) and (+)-barbatus01 (3) ' have been reported. We present here the first total synthesis of (+)isopisiferin (lc) and the related model compounds (la) and (lb) by a simple and general convergent route.. .