Criticism
In a 2007 paper Phil Baran notes that even though the textbooks state that the use of protective groups is unavoidable and that they are ideally easily added and removed, in practical terms in organic synthesis their use adds two synthetic steps (protection-deprotection sequence) to a chemical sequence and sometimes dramatically lowers chemical yield. Crucially, added complexity impedes the use of synthetic total synthesis in drug discovery. In contrast biomimetic synthesis does not employ protective groups. As an alternative, Baran presented a novel protective-group free synthesis of the compound hapalindole U. The previously published synthesis according to Baran, contained 20 steps with multiple protective group manipulations (two confirmed):
| Hapalindole U Baran 2007 protective-group free | Hapalindole U Muratake 1990 Ts protective groups in blue |
Read more about this topic: Protecting Groups
Famous quotes containing the word criticism:
“Homoeopathy is insignificant as an art of healing, but of great value as criticism on the hygeia or medical practice of the time.”
—Ralph Waldo Emerson (1803–1882)
“In criticism I will be bold, and as sternly, absolutely just with friend and foe. From this purpose nothing shall turn me.”
—Edgar Allan Poe (1809–1845)
“It is the will of God that we must have critics, and missionaries, and Congressmen, and humorists, and we must bear the burden. Meantime, I seem to have been drifting into criticism myself. But that is nothing. At the worst, criticism is nothing more than a crime, and I am not unused to that.”
—Mark Twain [Samuel Langhorne Clemens] (1835–1910)