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:
“Parents sometimes feel that if they don’t criticize their child, their child will never learn. Criticism doesn’t make people want to change; it makes them defensive.”
—Laurence Steinberg (20th century)
“When you overpay small people you frighten them. They know that their merits or activities entitle them to no such sums as they are receiving. As a result their boss soars out of economic into magic significance. He becomes a source of blessings rather than wages. Criticism is sacrilege, doubt is heresy.”
—Ben Hecht (1893–1964)
“I consider criticism merely a preliminary excitement, a statement of things a writer has to clear up in his own head sometime or other, probably antecedent to writing; of no value unless it come to fruit in the created work later.”
—Ezra Pound (1885–1972)