Double Methylenecyclopentane Annulation of Succinimides: Easy Access to 3,7‐Dioxobicyclo[3.3.0]octane‐1,5‐dicarboximides

Abstract

Keywords: Alkylation / Annulation / Carbocycles / Lithiation / Ozonolysis N-Alkylsuccinimides reacted with excess of LHMDS and 3-chloro-2-(chloromethyl)-1-propene to give in medium yields N-alkyl-3,7-dimethylenebicyclo[3.3.0]octane-1,5-dicarboximides, which were ozonized to the corresponding 3,7-dioxobicyclo[3.3.0]octane-1,5-dicarboximides. When these alkylations were carried out by using LDA as the base, cis-N-

An Entry to Functionalized 2,8-Ethanonoradamantane Derivatives

“…The starting compound 4 was recently described by our group . To transform compound 4 into alkylating agent 3 , we first submitted 4 to hydroboration with 9-borabicyclo[3.3.1]nonane (9-BBN) followed by oxidation with aqueous 35% H 2 O 2 under basic conditions.…”

“…The starting compound 4 was recently described by our group. 14 To transform compound 4 into alkylating agent 3, we first submitted 4 to hydroboration with 9-borabicyclo[3.3.1]nonane (9-BBN) followed by oxidation with aqueous 35% H 2 O 2 under basic conditions. Although we obtained the desired alcohol 5 as a mixture of stereoisomers, we could not separate it from the cis-cyclooctane-1,5-diol, formed as a byproduct.…”

Attempted synthesis of 2-oxo-N-phenyltetracyclo[7.2.1.02,6.05,11]-dodecane-9,10-dicarboximide by intramolecular α-ketocarbene insertion into an unactivated C-H bond

“…The combined organic extracts were dried (Na 2 SO 4 ) and concentrated to dryness in vacuo to give a residue (4.89 g) that was subjected to column chromatography (silica gel, 152 g, hexane/EtOAc). On elution with hexane/ 4 (4.5 mL) and stirring till complete dissolution. To a cold (0 ºC, ice-water bath) solution of alcohol 2 (618 mg, 2.0 mmol) in acetone (15 mL), part of the Jones reagent prepared above (3.0 mL, 6.8 mmol H 2 CrO 4 ) was added dropwise keeping the temperature at 0 ºC.…”

“…Recently, we described an easy access to compound 1 (Scheme 1) by double alkylation of the dianion derived from endo-N-phenylnorbornane-2,3-dicarboximide with 3-chloro-2-chloromethyl-1-propene. 4 We envisaged that compound 6 might be prepared from alkene 1 as shown in Scheme 1, the keystep consisting of an intramolecular insertion of an α-ketocarbene, generated from diazoketone 5, into an unactivated C-H bond with formation of a seven-membered ring. These types of transformations are well known and have been widely applied to the elaboration of three to sixmembered rings, formation of five-membered rings being usually preferred.…”