Stilbenes solid support

A short and efficient synthetic approach to hydroxy-substituted ( )-stil-benoids, as exemplified by the natural compound resveratrol (371b) via solid-phase CM, was reported by a Korean group (Scheme 71) [154]. When two different stilbenes were allowed to couple by catalyst C, all three kinds of possible stilbenes were obtained as an inseparable mixture. Anchoring 4-vinylphenol to Merrifield resin, followed by exposing the supported styrenyl ether 368 and diacetoxy styrene 369 (10 equiv) to the catalyst, inhibited self-metathesis of the supported substrate. Sequential separation of the homodimer formed from 369 by washing and subsequent cleavage of the resin 370 with acid provided (E)-stilbene 371a with complete stereocontrol in 61% yield. 

Another example of a chiral polymer that can be used in solution and recovered as a solid is the copolymer 73 [ 110]. This soluble block copolymer-supported ligand was very effective both in terms of synthetic yield and stereoselectivity in an asymmetric dihydroxylation of (E)-stilbene (Eq. 27) with an average synthetic yield of 84% and an average e.e. of 98% through five cycles. 

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