1 Introduction ................................................. 1
2 Objectives ................................................... 9
3 Results and Discussions ..................................... 11
3.1 Synthesis of the tricyclic sultones 8 .................. 11
3.1.1 Retrosynthetic analysis of the tricyclic
sultones 8 ...................................... 11
3.1.2 Preparation of TBS protected a-hydroxy esters
16 .............................................. 12
3.1.3 Conversion of esters 16 to Weinreb amides 14 .... 12
3.1.4 Homologation of 14 to give γ-hydroxy ketones
17 .............................................. 13
3.1.5 Oxidation of alcohols 17 to afford aldehydes
13 .............................................. 14
3.1.6 Chain extension of aldehydes 13 to afford
β-keto esters 23 ................................ 15
3.1.7 Diazo transfer with 23 to give α-diazo-β-keto
esters 12 ....................................... 15
3.1.8 Desilylation of 12 to furnish alcohols 26 ....... 16
3.1.9 Esterification of alcohols 26 to afford
vinylsulfonates 9 ............................... 17
3.1.10 Studies on the CCCC reaction .................... 17
3.1.11 Summary ......................................... 21
3.2 Synthetic approach towards the tetracyclic sultone
10a .................................................... 22
3.2.1 Retrosynthetic analysis of the tetracyclic
sultone 10a ..................................... 22
3.2.2 Attempt of preparation of 32 .................... 22
3.2.3 Alkylationof32a to afford 47 .................... 25
3.2.4 Conversion of 47 to 31a ......................... 26
3.2.5 Ozonolysis of olefin 31a to give the aldehyde
53 .............................................. 27
3.2.6 Chain extension of the aldehyde 53 to afford
the β-keto ester 54 ............................. 28
3.2.7 Diazo transfer with 54 to give α-diazo-β-keto
ester 30 ........................................ 29
3.2.8 Attempts towards desilylation of 30 ............. 29
3.2.9 Summary ......................................... 32
3.3 Synthesis of tetracyclic sultone (+)-10b ............... 33
3.3.1 Retrosynthetic analysis of the tetracyclic
δ-sultone 10b ................................... 33
3.3.2 Synthesis of 1,3-diketone 31b from triol 49 ..... 34
3.3.3 Asymmetric transfer hydrogenation (ATH) with
31b ............................................. 34
3.3.4 Protection of β-hydroxyketone (S,S)-60 as
benzoate 73 ..................................... 39
3.3.5 Ozonolysis of olefin 73 to give aldehyde 74 ..... 40
3.3.6 Chain extension of aldehyde 74 to give β-keto
ester 75 ........................................ 40
3.3.7 Diazo transfer with β-keto ester 75 to afford
α-diazo-β-keto ester 59 ......................... 41
3.3.8 Desilylation of 59 to give alcohol 76 ........... 41
3.3.9 Esterification of 76 to give vinylsulfonate
11b ............................................. 43
3.3.10 The CCCC reaction of vinylsulfonate 11b ......... 44
3.3.11 Summary ......................................... 45
3.4 Studies on the enantioselective CCCC reaction .......... 46
3.5 The CCCC reaction of acrylate 80 ....................... 50
3.6 Studies on the ring opening of oxatricyclic sultones
8 ...................................................... 52
4 Conclusion and Outlook ...................................... 55
5 Experimental section ........................................ 63
5.1 General Methods ........................................ 63
5.2 Experimental procedures and spectral data .............. 65
5.2.1 Referring to Section 3.1 ........................ 65
5.2.2 Referring to Section 3.2 ........................ 89
5.2.3 Referring to Section 3.3 ....................... 102
5.2.4 Referring to Section 3.4 ....................... 119
5.2.5 Referring to Section 3.5 ....................... 120
5.2.6 Referring to Section 3.6 ....................... 123
6 Appendix ................................................... 131
Abbreviations ................................................. 133
References .................................................... 135
Acknowledgement ............................................... 141
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