1. C-H Insertion on sulfonyl compounds Synthesis of Plakortethers
Petroleum products are an excellent source of relatively simple organic compounds. Developments of methods for their diversification provides synthetic intermediates that can be used in the synthesis of biologically active natural products.
C-H Insertion on sulfonyl compounds
Synthesis of Plakortethers
Studies on selectivity and scope
R1 R2 R3 R4
Cat
Product 2
Product 3
Me Me H H
Rh2(OAc)4
55% -
Me H H H
60%, dr 5:1
~3%1
Me H H H
Rh2(esp)2
70%, dr 2:1
Rh2(pfb)4
25%, dr 1:1
52%1
H H H H
~2%1
28%1
Not detected
60%1
Me H Me H
50%, dr >10:12
20%1
~5%1
60%1,dr >10:12
Me H Me Me
80%1
Rh2(MEPY)4
50%, ee 2%3
Rh2(DOSP)4
45%, ee 20%3
Rh2(PTTL)4
55%, ee 50%3
1 Combined for both diastereomers 2 At the b-carbon 3 For the trans-diastereomer
Conclusion: Identified catalysts and structural features that influence preference for formation of 6 and 5 membered rings.
Synthetic transformations
Studies on the synthesis of Terpiodiene
Alkylation
R1 R2 n X E+
Yield
Me Me 2 CH2
Allyl bromide
95%
EtI
80%
Me H 2 CH2
90%, single diastereomer
BnBr
95%, single diastereomer
Me Me 2 O
85%
Me H 1 CH2
C-S bond scission