27763-55-9Relevant academic research and scientific papers
Stereodivergent Construction of Vicinal Acyclic Quaternary-Tertiary Carbon Stereocenters by Michael-Type Alkylation of α,α-Disubstituted N- tert-Butanesulfinyl Ketimines
Liu, Hui,Lu, Chong-Dao,Yao, Yun,Yisimayili, Nuermaimaiti
supporting information, p. 7450 - 7455 (2021/10/02)
Vicinal quaternary-tertiary carbon stereocenters were constructed with excellent stereoselectivity via aza-enolization of enantioenriched acyclic N-tert-butanesulfinyl ketimines bearing two sterically similar α-linear alkyl substituents followed by conjugate addition to nitroalkenes. Further changes of the absolute configuration of the sulfinyl group and/or the α-stereocenter in the ketimine allowed the facile stereodivergent synthesis of all four diastereomers of the Michael-type alkylation adducts. This reaction is a successful example of acyclic stereocontrol based on stereoselective α-deprotonation for the formation of fully substituted aza-enolates from ketone derivatives.
An Asymmetric Synthesis of Acyclic and Macrocyclic α-Alkyl Ketones. The Role of (E)- and (Z)-Lithioenamines
Meyers, A. I.,Williams, Donald R.,White, Steven,Erickson, Gary W.
, p. 3088 - 3093 (2007/10/02)
Metalation and alkylation of chiral imines derived from C10, C12, and C15 cyclic ketones gave, under kinetic metalation conditions, 2-alkylcycloalkanones of absolute configuration opposite to that formed from thermodynamic metalation.Thus, (S)-(-)-2-methylcyclododecanone is formed kinetically in 60percent ee, whereas (R)-(+)-methylcyclododecanone is reached in 80percent ee under thermodynamic conditions.In a similar fashion, acyclic ketones 20, via their chiral imines 17, are alkylated enantioselectively under both kinetic and thermodynamic modes.The kinetic metalation gives exclusively the (Z)-lithioenamines (19), while reflux of this lithio anion gives only the (E)-lithioenamine (19).Chiral α-substituted ketones are produced in 18-97percent ee.
