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Dissertation
Diastereoselective synthesis of protected secondary amines via reduction/alkylation or deprotonation/alkylation of N-diphenylphosphinylimines: synthesis of secondary amines via 1,2-addition of organometallic reagents to N-diphenylphosphinylimines and subsequent alkylation
Doctor of Philosophy (Ph.D.), Drexel University
2001
DOI:
https://doi.org/10.17918/00009736
Abstract
Part A. Stereoselectively protected secondary amines are prepared by reduction of a variety of substituted cyclohexyl N-diphenyphosphinylcyclohexylidineimines with lithium-tri-sec -butylborohydride approach of which is found to occur from the less sterically hindered equatorial face leading to the corresponding axial lithium anions, followed by the treatment with methyliodide. In the same way, the stereoselectively protected secondary amines are prepared by alkylation of the corresponding axial/equatorial lithiated anions, which are produced from stereoselectively formed axial and equatorial substituted N-diphenylphosphinylcyclohexylamines reduced by L-selectride or t-butylamine-borane complex, respectively under basic conditions such as n-butyl lithium or KHDMS yielded the corresponding lithium anions which were reacted with alkyl halides to afford the corresponding stereoselectively protected N-alkylated secondary amines. Part B. Alkylation of N-diphenylphosphinyl imines is a direct and facile route for obtaining the protected secondary N-diphenylphosphinyl amines. The addition of organolithium to N-diphenylphosphinyl imines formed the anion of N-diphenylphosphinyl amides which can serve as nucleophiles. The subsequent alkylation of the anion of N-diphenylphosphinyl amides with alkyl halides provided the corresponding alkylated N-diphenylphosphinyl amides. The synthesis of simple protected secondary amines which were produced from N-diphenylphosphinyl aldehyde imines were used as electrophiles to react with orgnometallic reagents such as n-BuLi, PhLi, and CH3Li to form the anion which was alkylated to the corresponding amides by treatment with alkyl halides.
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Details
- Title
- Diastereoselective synthesis of protected secondary amines via reduction/alkylation or deprotonation/alkylation of N-diphenylphosphinylimines
- Creators
- Hyun-shun Shin
- Contributors
- Robert O. Hutchins (Advisor) - Drexel University, Drexel University (1970-)
- Awarding Institution
- Drexel University
- Degree Awarded
- Doctor of Philosophy (Ph.D.)
- Publisher
- Drexel University; Philadelphia, Pennsylvania
- Number of pages
- x, 240 pages
- Resource Type
- Dissertation
- Language
- English
- Academic Unit
- College of Arts and Sciences; Drexel University
- Other Identifier
- 991021888940604721