Protecting group-free flow synthesis

Scheme 7.9 Protecting group-free flow synthesis selective O-acylation oftyramine (7) based on a "catch and release concept.

Kim H, Nagald A, Yoshida J (2011) A flow-microreactor approach to protecting-group-free synthesis using organolithium compounds. Nat Commun 2 264... 

A typical synthesis of complex organic molecules involves multiple reaction steps with intermediate purification of the intermediates. Such synthetic routes require a lot of labor-intensive manipulations and generate a lot of waste (e.g., solvents). With the atom-efficient biosynthetic pathways in cells as a model, several approaches have been developed in order to facilitate synthetic chemistry, such as protecting group-free syntheses [46], one-pot syntheses [47], cascade reactions [48], and multicomponent reactions [49]. More recently, synthetic chemists have been attracted by flow chemistry since it allows to combine all these processes in a single streamlined continuous process (i.e., multistep one-flow synthesis) [50]. Several strategies have been developed. 

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