17.5 15-Membered Macrocyclic Lactones
17.5.1 (+)-Halichlorine
During the total synthesis of (+)-halichlorine 229, the 15-membered macrocycle
228 was isolated in acceptable yield (54 %) using a EDC-modified Boden–Keck
macrolactonization protocol [146] (Scheme 65).
17.6 16-Membered Macrocyclic Lactones
17.6.1 Pamamycin-607
Sometimes, DMAP can be detrimental to the macrolactonization procedure due to
epimerizations and formation of intractable reaction mixtures. Therefore, in the
synthesis of pamamycin-607 232, a Keck-type DCC/pyridine/PPTS protocol was
Scheme 63 The Boden–Keck protocol in the synthesis of diazonamide A-related biaryl 223
Scheme 64 The Boden–Keck protocol in the total synthesis of (–)-colletol, 226
418
M. Cordes and M. Kalesse
17.5.1 (+)-Halichlorine
During the total synthesis of (+)-halichlorine 229, the 15-membered macrocycle
228 was isolated in acceptable yield (54 %) using a EDC-modified Boden–Keck
macrolactonization protocol [146] (Scheme 65).
17.6 16-Membered Macrocyclic Lactones
17.6.1 Pamamycin-607
Sometimes, DMAP can be detrimental to the macrolactonization procedure due to
epimerizations and formation of intractable reaction mixtures. Therefore, in the
synthesis of pamamycin-607 232, a Keck-type DCC/pyridine/PPTS protocol was
Scheme 63 The Boden–Keck protocol in the synthesis of diazonamide A-related biaryl 223
Scheme 64 The Boden–Keck protocol in the total synthesis of (–)-colletol, 226
418
M. Cordes and M. Kalesse