Linchpin coupling, three-component

A large number of macrolide natural products contain long, stereodefined polyol fragments. In their original report on the linchpin three-component coupling... 

The viabihty of this new Type II ARC involving threefold domino reactions was demonstrated by developing a one-flask three component coupling protocol using 1,3-dithiane epoxy compound 176 as linchpin (Scheme 4.33) [59]. Thus,... 

Scheme 4.33 Domino three-component ARC II coupling of linchpin 176.

Smith and coworkers next extended Type II ARC domino protocol beyond dithiane arena by designing a variety of effective ARC linchpins with different ASGs capable of three and four component couplings. In their first effort toward this goal, they developed readily available 2-bromoallylsilane [62a], and subsequently, allyltrimethylsilane 185 [63], and recently o-TMS (trimethylsilyl) benzaldehyde 188 as promising linchpins for Type II ARC process [64, 65]. However, domino anionic relay reactions with these linchpins 185 and 188 are not discussed in this chapter, since they are not initiated by nucleophilic substitution as the first step. 

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