Bis-homoketonization of some 4,5-disubstituted homocubyl derivatives

Cyclopropanol chemistry

“…As with Nickon's system, exo addition of the proton (with inversion) was confirmed when the rearrangements were performed in deuterated solvent. 81 Hamon and Sinclair57 generated homoenolate ions by the action of an alkali metal on a /3-halogenated aldehyde and a related ketone. Acylation of the resulting anions gave cyclopropylacetates in yields of about 50%.…”

“…The reactions of 1-vlnylcyclopropanol and the corresponding ethynyl compound with electrophilic agents con- Reaction of the ethyl hemiketal of eyclopropanone with sodium azide afforded a /3-lactam in low yield. Later studies then showed that the /3-lactams could be formed in better yields from aminals or carbinolamines; reaction 81 The synthetic uses of oxaspiropentanes are being studied and developed by two groups. A cyclobutanone was obtained by Trost from a reaction (eq 82) thought to involve an inter-…”

Acid homoketonization with inversion of configuaration. Dramatic effect of water in control of stereochemistry

“…give only norbornene and MesSnOAc at 25°. The syn-endo isomer 4b yields a mixture (100°) composed of 65% exo-2-norbornyl acetate (7), 3.4% exo-2-norbornanol (8), 16% endo-2-norbornyl acetate (9), 16% 7-norbornyl acetate (10), and an equivalent of MesSnOAc. For comparison, exo-2-norbornyl mesylate (5b) gives (25°) 94.5% 7, 4.2% 8, and 1.3% nortricyclene, whereas only 7 was observed from the solvolysis of 6b at 100°.…”

Strained bridgehead cage alcohols and derivatives

“…An interesting bishomoketonization process has been reported by Miller and Dolce for 4,5-dihydroxyhomocubane (24b) and its bis(trimethylsilyl) ether (24a). 77 With NaOMe in MeOH at room temperature both compounds rapidly react to afford diketone 106 (D = H) in 50-60% yield as the only isolable product (Scheme 53). Deuterium-labeling experiments show this information of 106 to be a stereospecific process in which two deuterons are incorporated, one into an exo position and one into an endo position.…”