113297-14-6Relevant articles and documents
α-Bromo Spiroketals: Stereochemistry and Elimination Reactions
Lawson, Elvie N.,Kitching, William,Kennard, Colin H. L.,Byriel, Karl A.
, p. 2501 - 2508 (1993)
The simple spiroketals, 1,6-dioxaspirononane (2), 1,6-dioxaspirodecane (5), 1,7-dioxaspiroundecane (6), and (E,E)-2,8-dimethyl-1,7-dioxaspiroundecane (7), have been brominated by bromine in carbon tetrachloride/calcium carbonate or acetic acid, and a number of mono-, di-, and tribromo derivatives have been characterized.The relative stereochemistries have been established by correlated 1H and 13C NMR spectroscopy and X-ray crystal structure determinations.Dehydrobromination with potassium tert-butoxide in either dimethyl sulfoxide or tetrahydrofuran is facile for the axial monobromides, although both axial and equatorial bromides derived from 1,6-dioxaspirodecane (5) and 1,7-dioxaspiroundecane (6) dehydrobromate to provide 1,6-dioxaspirodec-9-ene (35) and 1,7-dioxaspiroundec-4-ene (26), respectively.Hydration of these readily acquired alkenes furnishes the corresponding 9- and 4-ols, respectively, with the latter being components of the rectal glandular secretion of Bactrocera oleae (olive fly), Bactrocera cacumintas, and Bactrocera distincta.These studies indicate that α-bromination of suitable spiroketals may be a viable later step in the synthesis of α-bromine-containing spiroketal metabolites such as obtusin and neoobtusin.
Allylic functionalization of the 1,7-dioxaspiro[5.5]-undec-4-ene and 1,6,8-trioxadispiro[4.1.5.3]-pentadec-13-ene ring systems
Brimble,Edmonds,Williams
, p. 6455 - 6466 (1992)
Allylic bromination of the bicyclic spiroacetals 5,6 and 7 gave predominantly the axial bromides 15, 21 and 23 which underwent S(N)2 displacement to the equatorial alcohols 17, 22 and 25 respectively, using potassium superoxide and 18-crown-6 in THF/DMSO (10:1). Allylic bromination of the cis-bis-spiroacetal 26 gave predominantly the rearranged allylic bromide 29 which afforded alcohols 30 and 31 resulting from both S(N)2 and S(N)2 displacement upon treatment with potassium superoxide. Bromination of the trans-bis-spiroacetal 27 afforded a complex mixture from which only the non-rearranged bromide 34 could be isolated. This bromide 34 afforded the axial alcohol 37 upon treatment with potassium superoxide.
A highly efficient access to spiroketals, mono-unsaturated spiroketals, and furans: Hg(II)-catalyzed cyclization of alkyne diols and triols
Ravindar, Kontham,Sridhar Reddy, Maddi,Deslongchamps, Pierre
supporting information; experimental part, p. 3178 - 3181 (2011/08/06)
Hg(II) salts are identified as highly efficient catalysts for the versatile construction of spiroketals from alkyne diols in aqueous conditions. Monounsaturated spiroketals and furans were accessed with equal ease when propargylic triols (or propargylic d
A palladium mediated spiroketal synthesis
Conway, Jeremy C.,Quayle, Peter,Regan, Andrew C.,Urch, Christopher J.
, p. 85 - 88 (2007/10/03)
A Stork-Negishi olefination-coupling sequence has been applied to the synthesis of spiroketals.
