137166-10-0Relevant academic research and scientific papers
Synthetic Studies on Tricyclospirodienones; Model Chemistry for Novel Mimics of Steroid Substrates
Hares, Owen,Hobbs-Mallyon, David,Whiting, Donald A.
, p. 1481 - 1492 (2007/10/02)
As part of a programme to synthesize aryltricyclospirodienones 3, potential steroid antimetabolites, the formation of tricyclospirodienones 4 from substituted tetralins has been studied. 1-Allyl- and 1-(but-3-enyl)-tetralins 9 and 11 were synthesized from the 6-alkoxytetralols 8 and the corresponding pivaloates 10 using allytrimethylsilane/zinc iodide and 1-(but-3-enyl)magnesium bromide respectively, and were used to prepare the epoxides 20 and 21, the iodides 13, 16 and 19, and the nitro compounds 14 and 17.Phenol-exo-spirocyclisations of the iodides were shown to proceed smoothly in the 5- and 6-exo-tet senses; in contrast, the epoxides failed to cyclise in these formally allowed modes and only the 7-endo type, i.e. 21 (α-H) -> 30 was viable.Cyclisation via phenylthiiranium and phenylselenonium ions followed a similar pattern.Under acid catalysis the epoxide 21 formed the 5-exo products 36 and 37, which on further acid treatment gave the tetracycles 38 and 39 respectively.The α-oxocarbocation from the diazo ketones 41 provided the spirodienone 43.The ω-nitropropyl and ω-nitrobutyl-6-hydroxytetralins 14c and 17c underwent stereospecific intramolecular coupling between phenolate and nitronate functions to afford tricyclospirodienones 46 and 47 respectively.
Spirocyclisation Modes in the Formation of Tricyclospirodienones
Hobbs-Mallyon, David,Whiting, Donald A.
, p. 2277 - 2278 (2007/10/02)
Pheno-exo spirocyclisations of phenolic iodides 7-9 have been shown to proceed smoothly in the 5- and 6-exo-tet senses; in contrast the phenolic epoxides 13-15 fail to cyclise in these formally allowed modes and only the 7-endo type, e.g. 14a ->16 is viable: cylisation via phenylthiiranium ions follows a similar pattern.
