114222-08-1Relevant articles and documents
Amphiphilic Reactions by Means of Exceptionally Bulky Organoaluminum Reagents. Rational Approach for Obtaining Unusual Equatorial, Anti-Cram, and 1,4 Selectivity in Carbonyl Alkylation
Maruoka, Keiji,Itoh, Takayuki,Sakurai, Minoru,Nonoshita, Katsumasa,Yamamoto, Hisashi
, p. 3588 - 3597 (2007/10/02)
Exceptionally bulky, oxygenophilic organoaluminum reagents, methylaluminum bis(2,6-di-tert-4-alkylphenoxide) (MAD and MAT), have been successfully utilized for stereoselective activation of carbonyl moiety.Combination of MAD or MAT with carbon nucleophiles such as organolithiums or Grignard reagents generates a new amphiphilic reaction system in which the alkylation may be interpreted as the nucleophilic addition of a reactive organometallic compound to an electrophilically activated carbonyl substrate in order to account for the regio- and stereochemical consequences.In contrast to the ordinary alkylations, the amphilic alkylation disclosed herein would be categorized into the new, yet unexplored class of alkylation that exhibits high chemoselectivity to carbonyl compounds, and more significantly it allows excellent equatorial and anti-Cram selectivity in carbonyl alkylations, hitherto difficult by the existing methodologies.Further, unusual conjugate addition of organolithium reagents to α,β-unsaturated carbonyl compounds has been accomplished by using the amphiphilic reaction system.
Enhanced Cram Selectivity in Carbonyl Alkylation via 'Naked ' Anions and anti-Cram Selectivity via 'Naked' Cuprates
Yamamoto, Yoshinori,Matsuoka, Koshin
, p. 923 - 924 (2007/10/02)
Enhanced Cram selectivity is observed via the reaction of aldehydes (1) with 'naked' anions (2) prepared in situ from RM and Bu4NBr, while anti-Cram selectivity results from the reaction of (1) with 'naked' cuprates (4) prepared in situ from R2CuLi and Bu4NBr.