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Title: Lewis base organocatalysts for carboxyl and acyl transfer reactions
Author: Woods, Philip A.
ISNI:       0000 0004 2722 5162
Awarding Body: University of St Andrews
Current Institution: University of St Andrews
Date of Award: 2011
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This thesis is concerned with the use of Lewis base organocatalysts for carboxyl and acyl transfer reactions. Chapter 1 introduces the ability of organic Lewis bases other than DMAP-type to promote a range of asymmetric O-, N- and C-acyl transfer processes. This chapter summarizes the developments in catalyst architectures and approaches to these processes that have been disclosed to date in this dynamic area of asymmetric organocatalysis. Chapter 2 introduces studies into the synthesis of pyrrolyl carbonates via cyclization of gamma-amino esters and ring closing metathesis (RCM) of N-allylamides. The ability of a range of Lewis bases to promote the regioselective O- to C-carboxyl transfer of pyrrolyl carbonates is also presented. Chapter 3 introduces isothiourea DHPB as an efficient Lewis base catalyst for the diastereoselective C-acylation of silyl ketene acetals with anhydrides or benzoyl fluoride, giving 3-acyl-3-aryl or 3-acyl-3-alkylfuranones in excellent yields and stereoselectivities (up to 99:1 dr). Chapter 4 introduces C(2)-aryl substituted DHPB derived-isothioureas as efficient Lewis base catalysts for the enantioselective C-acylation of silyl ketene acetals with propionic anhydride, giving 3-acyl-3-aryl or 3-acyl-3-alkylfuranones in good isolated yields and enantioselectivities (up to 98% ee). This chapter also demonstrates that these chiral isothioureas are required for high reactivity and asymmetry in related acylation manifolds. Chapter 5 presents and overall conclusion for chapters 2,3 and 4. Chapter 6 contains full experimental procedures and characterization data for all compounds synthesized in Chapters 2, 3 and 4.
Supervisor: Smith, Andrew D. Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available
Keywords: Asymmetric organocatalysis ; Lewis base catalysts ; Carboxyl and acyl transfer reactions