Armed/disarmed strategy/effect

Since discovery of the armed/disarmed strategy for chemoselective coupling of sugars (16), several modifications have been tested to develop more nuanced effects (27). The process of discovery continues with a recent observation in Demchenko s lab shown in Scheme 11 (28). On the basis of the (now classical ) precedents shown in Scheme 6, the 02-benzoyl group of 61 and... 

The classic armed-disarmed approach, developed by Fraser-Reid, has created a solid basis for extensive studies and applications, and all strategies discussed in this section are related to (or derived from) this elegant concept. The key factor for the armed-disarmed activation to take place is the availability of a suitable promoter that differentiates between the armed and disarmed building blocks. While in most cases the differentiation of the reactivity between armed and disarmed species is maintained by the choice of promoter or temperature, the solvent effect observed by Oscarson may become a useful technique for future assemblies.160 Thus, it was demonstrated that highly reactive substrates could be activated in diethyl ether, whereas poorly reactive disarmed derivatives had to be activated in CH2CI2. 

---