112522-04-0Relevant articles and documents
The Asymmetric Synthesis of 2,2-Dialkyl Carboxylic Esters and 2,2-Disubstituted Dihydronaphthalenes
Meyers, A. I.,Wallace, Richard H.,Harre, Michael,Garland, Robert
, p. 3137 - 3143 (2007/10/02)
The bicyclic lactams derived from (S)-valinol and 3-benzoylpropionic acid or levulinic acid are useful chiral precursors to the title compounds.Metalation of bicyclic lactams 1 and 4 and alkylation followed by acidic hydrolysis leads to racemic 2-alkyl carboxylic acids.However, sequential metalation-alkylation to 2,2-dialkyl bicyclic lactams 2 and 5 furnishes these systems with good diastereoselectivity.Treatment of 5 with triflic acid causes a facile rearrangement to the oxalines 7 and hydrolysis leads to the carboxylic esters.Under certain conditions, hydrolysis leads directly to naphthalenes 11.
AN ASYMMETRIC SYNTHESIS OF 4,4- AND 6,6-DIALKYLCYCLOHEXENONES AND 4,4- AND 5,5-DIALKYLCYCLOPENTENONES. APPLICATION TO THE TOTAL SYNTHESIS OF (-)-SILPHIPERFOL-6-ENE
Meyers, A. I.,Lefker, Bruce A.
, p. 5663 - 5676 (2007/10/02)
Chiral amino alcohols have been transformed into bicyclic lactams 1 and 6 which, after metalation and alkylation, gave high diastereomeric ratios of 2,2-dialkyl quaternaly products, 29 and 12, respectively.Addition of organolithium reagents to the carbonyl of these lactams, followed by acidic cleavage, leads to enantiomerically pure cyclohex-2-enones and cyclopent-2-enones.This process was also applied to a key, chiral cyclopentenone 39, which was used by Curran, in racemic form, to prepare the angular triquinane, silphiperfol-6-ene.The total asymmetric synthesis was carried out in 6.6percent yield over nine steps.
