Chemistry of N-Boc-N-tert-butylthiomethyl-protected alpha-aminoorganostannanes: diastereoselective synthesis of primary beta-amino alcohols from alpha-aminoorganostannanes.
Reaction of N-Boc-N-tert-butylthiomethyl-protected alpha-aminoorganostannanes with n-BuLi generates the corresponding alpha-aminoorganolithiums. Reactions of these organolithiums with aromatic aldehydes provides N-protected beta-amino alcohols with diastereoselectivities up to >99:1 anti/syn; with aliphatic aldehydes, diastereoselectivities were typically 1:1. Diastereoselectivities varied depending on the amount of aldehyde used. The N-protected beta-amino alcohols could be deprotected to primary amines by treatment with NaH to generate oxazolidinones followed by basic hydrolysis. Alternatively, treatment of the protected amino alcohols with acid furnished cyclic acetals that could be deprotected to primary amines with BF(3).OEt(2) and HS(CH(2))(3)SH. Transmetalation of enantiomerically enriched organostannanes with n-BuLi at -95 degrees C provided organolithiums that, although less configurationally stable than N-Boc-N-methyl-protected alpha-aminoorganolithiums, could be trapped with aldehydes with near-complete retention of configuration.
Ncube
Adela
A
Guelph-Waterloo Centre for Graduate Work in Chemistry and Biochemistry (GWC(2)), Department of Chemistry, University of Waterloo, Waterloo, Ontario, Canada N2L 3G1.
Park
Sheldon B
SB
Chong
J Michael
JM
D000605:Amino Alcohols / Q000138:chemical synthesis*; D005563:Formic Acid Esters / Q000737:chemistry; D008094:Lithium / Q000737:chemistry; D008968:Molecular Conformation; D009947:Organotin Compounds / Q000737:chemistry*; D013237:Stereoisomerism; D013379:Substrate Specificity; D017971:Tin Compounds / Q000737:chemistry*
D000605:Amino Alcohols; D005563:Formic Acid Esters; D009947:Organotin Compounds; D017971:Tin Compounds; C000345:t-butyloxycarbonyl group; C031525:stannane; D008094:Lithium