Bio-Inspired Strategies

FIGURE 9.4 Radial hexagons for (-)-paclitaxel total and semisyntheses given in Table 9.2. 

Despite the rosy outlook of these examples, there are serious problems that need addressing from a green chemistry point of view. These are itemized as follows  

FIGURE 9.6 D-glucose as a biofeedstock for a variety of target molecules [40-44]. 

The real mechanism may involve metal cofactors in a dioxygenase enzyme according to the following scheme using iron as an arbitrarily chosen metal ion. 

At this time, since the mechanism is nnknown the simpler mechanism was used to calculate metrics. What can be said with certainty is that until all of the problems itemized earlier are resolved by serious fundamental research there can be no credible way to prove the greenness of these kinds of transformations from either a material or energy consumption point of view. 

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Well-defined amphiphilic block copolymers can be prepared by various controlled polymerization reactions, such as atom transfer radical polymerization (ATRP), reversible addition-fragmentation chain transfer (RAFT), and nitroxide mediated polymerization (NMP). The amphiphilic copolymers most frequently used in bio-inspired strategies consist of hydrophilic blocks, such as poly(aciylic acid) (PAA), poly(ethylene oxide) (PEO), or poly(2-methyl oxazoline) (PMOXA), and a hydrophobic block, such as... 

Figure 5.3 General structure of the algorithm for the advanced control approach. Adapted from Hristu-Varsakelis D, Shao C. A bio-inspired pursuit strategy for optimal control with partially constrained final state. Automatica 2007 43(7) 1265—1273.

Kirschner CM, Brennan AB Bio-inspired antifouling strategies. In Clarke DR, editor ... 

In this overview, several strategies of bio-inspired crystallization with hydrophilic polymer additives have been presented. The most well known... 

Turicchia, L., and R. Saipeshkar. 2005. A bio-inspired companding strategy for spectral enhancement. IEEE Transactions on Speech and Audio Processing 13(2) 243—253. 

The Aspidosperma family of indole alkaloids has inspired many synthetic strategies for the construction of their pentacyclic framework of the parent compound aspidospermidine (366), since the initial clinical success of two derivatives, vinblastine (10) and vincristine, as anticancer agents. The alkaloids such as (-)-rhazinal (369) and (-)-rhazinilam (6) have been identified as novel leads for the development of new generation anticancer agents [10,11]. Bis-lactams (-)-leucunolam (370) and (-t-)-epi-leucunolam (371) have bio-genetic and structural relationships with these compounds [236]. Recently, enantioselective or racemic total syntheses of some of the these natural product were achieved. One successful synthesis was the preparation of the tricyclic ketone 365, an advanced intermediate in the synthesis of aspidospermidine (366), from pyrrole (1) (Scheme 76) [14]. The key step is the construction of the indolizidine 360, which represents the first example of the equivalent intramolecular Michael addition process [14,237,238]. The DIBAL-H mediated reduction product was subject to mesylation under the Crossland-... 

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