The synthesis of isochroman-4-ols and isochroman-3-ols: models for naturally occurring benzo[g]isochromanols

The 6π-azaelectrocyclization of azatrienes. Synthetic applications in natural products, bioactive heterocycles, and related fields

Covering: 2006 to 2018 The application of the 6π-azaelectrocyclization of azatrienes as a key strategy for the synthesis of natural products, their analogs and related bioactive or biomedically-relevant compounds (from 2006 to date) is comprehensively reviewed. Details about reaction optimization studies, relevant reaction mechanisms and conditions are also discussed.

Total Synthesis of Phorboxazole B

An efficient and highly convergent total synthesis of the potent antitumor agent phorboxazole B has been achieved. The synthetic strategy of this synthesis features: 1) a highly efficient substrate-controlled hydrogenation to construct the functionalized cis-tetrahydropyrane unit; 2) iterative crotyl addition to synthesize the segment that contains alternating hydroxyl and methyl substituents; 3) Hg(OAc)2/I2-induced cyclization to establish the cis-tetrahydropyrane moiety; 4) 1,3-asymmetric induction in the Mukaiyama aldol reaction to afford the stereogenic centers at C9 and C3; and 5) the exploration of the Still-Gennari olefination reaction to complete the macrolide ring of phorboxazoloe B.

Toward the Total Synthesis of Phorboxazole B: An Efficient Synthesis of the C20−C46 Segment

An efficient synthesis of the C20-C46 segment of phorboxazole B is described. The key steps involved Hg(OAc)(2)/I(2)-induced cyclization to construct the cis-tetrahydropyran moiety, the coupling of the metalated 2-methyloxazole 7 with lactone 6, and Julia olefination to furnish the conjugated diene moiety.

Ortho- and Para-Substituted Hoveyda−Grubbs Carbenes. An Improved Synthesis of Highly Efficient Metathesis Initiators

A novel highly efficient and general route to various 3- and 5-substituted 2-alkoxystyrenes, required for the preparation of Hoveyda-Grubbs catalysts, is described.