Abstract
Synthesis of the eastern hemisphere (C1-C15) of palmerolide
A is described. A re-optimized Claisen-type condensation of vinylogous
acyl triflates provides efficient entry into the C1-C8 subunit,
setting up a convergent Horner-Wittig olefination to deliver
the eastern portion of palmerolide A.
Key words
vinylogous acyl triflate - fragmentation - total
synthesis - palmerolide - methodology
References and Notes
1 Amsler CD.
Iken KB.
McClintock JB.
Baker BJ. In
Marine Chemical Ecology
McClintock JB.
Baker BJ.
CRC
Press;
Boca Raton FL:
2001.
p.267-300
2 Dayton PK.
Mordida BJ.
Bacon F.
Am.
Zool.
1994,
34:
90
3 Information available through the Antarctic
Treaty Secretariat: http://www.ats.aq/.
4a Diyabalange T.
Amsler CD.
McClintock JB.
Baker BJ.
J. Am. Chem. Soc.
2006,
128:
5630
4b Lebar MD.
Baker BJ.
Tetrahedron
Lett.
2007,
48:
8009
4c Riesenfeld CS.
Murray AE.
Baker BJ.
J. Nat. Prod.
2008,
71:
1812
5 Of the NCI’s panel of 60 cancer
cell lines, no other cell
6a Jiang X.
Liu B.
Lebreton S.
De Brabander JK.
6b Nicolaou KC.
Guduru R.
Sun Y.-P.
Banerji B.
Chen DY.-K.
Angew. Chem.
Int. Ed.
2007,
46:
5896
6c Jägel J.
Maier ME.
Synthesis
2009,
2881
6d Kaliappan KP.
Gowrisankar P.
Synlett
2007,
1537
6e Cantragrel G.
Meyer C.
Cossy J.
Synlett
2007,
2983
6f Chandrasekhar S.
Vijeender K.
Chandrasekhar G.
Reddy ChR.
Tetrahedron: Asymmetry
2007,
18:
2473
6g Jägel J.
Schmauder A.
Binanzer M.
Maier ME.
Tetrahedron
2007,
63:
13006
6h Penner M.
Rauniyar V.
Kaspar LT.
Hall DG.
J. Am. Chem. Soc.
2009,
131:
14216
7a Kamijo S.
Dudley GB.
J.
Am. Chem. Soc.
2005,
127:
5028
7b Jones DM.
Kamijo S.
Dudley GB.
Synlett
2006,
936
7c Kamijo S.
Dudley GB.
J. Am. Chem. Soc.
2006,
128:
6499
7d Kamijo S.
Dudley GB.
Org. Lett.
2006,
8:
175
8a Eschenmoser A.
Felix D.
Ohloff G.
Helv. Chim. Acta
1967,
50:
708
8b Felix D.
Shreiber J.
Ohloff G.
Eschenmoser A.
Helv. Chim. Acta
1971,
54:
2896
8c Tanabe M.
Crowe DF.
Dehn RL.
Tetrahedron
Lett.
1967,
3943
8d Tanabe M.
Crowe DF.
Dehn RL.
Detre G.
Tetrahedron Lett.
1967,
3739
9a Grob CA.
Schiess PW.
Angew. Chem., Int. Ed. Engl.
1967,
6:
1
9b Grob CA.
Angew. Chem., Int. Ed. Engl.
1969,
8:
535
9c Wharton PS.
Hiegel GA.
J.
Org. Chem.
1965,
30:
3254
9d Weyerstahl P.
Marschall H. In
Comprehensive
Organic Synthesis
Vol. 6:
Trost BM.
Fleming I.
Pergamon;
Oxford:
1991.
p.1041-1070
10a Kolakowski RV.
Manpadi M.
Zhang Y.
Emge TJ.
Williams LJ.
J. Am. Chem. Soc.
2009,
131:
12910
10b Draghici C.
Brewer M.
J.
Am. Chem. Soc.
2008,
130:
3766
11 Tummatorn J.
Dudley GB.
J. Am. Chem. Soc.
2008,
130:
5050
12 Maloney KM.
Chung JYL.
J. Org. Chem.
2009,
74:
7574
13 See Supporting Information, compound A .
14a Fürstner A.
Langemann K.
J.
Am. Chem. Soc.
1997,
119:
9130
14b Michaunt A.
Boddaert T.
Coquerel Y.
Rodriguez J.
Synthesis
2007,
18:
2687
15a Sharpless KB.
Amberg W.
Bennani YL.
Crispino GA.
Hartung J.
Jeong KS.
Kwong HL.
Morikowa K.
Wang ZM.
Xu D.
Zhang X.-L.
J.
Org. Chem.
1992,
57:
2768
15b Gurjar MK.
Pramanik C.
Bhattasali D.
Ramana CV.
Mohapatra
DK.
J.
Org. Chem.
2007,
72:
6591
16 Vatele J.-M.
Tetrahedron
Lett.
2006,
47:
715
17 See Supporting Information, compound B .
18 Cyclization of 5 predominated
using bases including Ba(OH)2 , DBU˙LiCl (Masamune-Roush
conditions), and KOt -Bu. A common feature
of these bases is that each is intermediate in basicity between
the initial β-keto phosphine oxide anion and the enolate
arising from undesired cyclization onto the enoate. Therefore, the
conjugate acid may play a role in promoting undesired cyclization (Scheme
[³
19 Corey EJ.
Helal CJ.
Angew. Chem. Int. Ed.
1998,
37:
1986
20 See Supporting Information, compound C .
