Synthesis of β-Amino-Substituted Enones by Addition of Substituted Methyl Enones to Sulfinimines: Application to the Total Synthesis of Alkaloids (+)-Lasubine II and (+)-241D and the Formal Total Synthesis of (-)-Lasubine I.

Addition of silyl enol ethers obtained from substituted methyl enones to chiral sulfinimines afforded the β-amino-substituted enones with excellent selectivity. Utility of the obtained N-sulfinyl β-amino ketones possessing α,β-unsaturation is exemplified in the total synthesis of the quinolizidine alkaloid natural products (-)-lasubine I, (+)-lasubine II, and substituted piperidine alkaloid (+)-241-D.