Stereoselective Total Synthesis of Phenolic Nonadecanediol

A simple and highly efficient synthetic route has been developed for synthesis of 1‐(4‐hydroxyphenyl)nonadecane‐3,5‐diol ( 1 ). The two stereogenic centers were generated by employing proline asymmetric α‐hydroxylation (MacMillan α‐hydroxylation), Jacobsen's hydrolytic kinetic resolution (HKR), and, finally, Yamaguchi oxirane opening as key steps (Scheme 2).     

Total synthesis of mangiferaelactone

Herein we document the first total synthesis of mangiferaelactone and thus establish its absolute configuration. The central nonenolide ring was constructed using ring closing metathesis and Yamaguchi esterification. The key alcohol fragment was synthesized by the Bernet–Vasella fragmentation of C-ribofuranoside.     

Total synthesis of proposed structure of xylogiblactone B by chiron approach

Total synthesis of the proposed structure of xylogiblactone B is described using d-(+)-mannitol, regioselective epoxide ring-opening, Yamaguchi esterification, and ring-closing metathesis as key steps.     

Total Synthesis of Umuravumbolide

A simple and efficient stereoselective total synthesis of (+)‐umuravumbolide ( 1b ) and (?)‐deacetylumuravumbolide ( 1a ) starting from commercially available pentanal is described. The synthesis involves Sharpless asymmetric epoxidation, Jacobsen's hydrolytic kinetic resolution (HKR), and the Yamaguchi oxirane opening as key steps (Scheme 2).     

Visible-Light Photoredox-Catalyzed Acyl Lactonization of Alkenes with Acyl Chlorides

A photocatalytic acyl lactonization of unsaturated carboxylic acids using simple and inexpensive acyl chlorides has been developed for a modular synthesis of acyl lactones. Significantly, the simple protocol could allow an efficient construction of biologically important phthalide framework. The transformation could be extended to a wide variety of unsaturated carboxylic acids, including substituted 2-vinyl benzoic acids and different types of alkenoic acids. Moreover, a series of aroyl, heteroaroyl chlorides could serve as coupling partners. Notably, functional groups including MeO, F, Cl and Br could survive. It is believed that acyl radicals generated from acyl chlorides under photoredox catalysis reacted with alkenes via atom-transfer radical addition (ATRA) and triggered subsequent lactonization in the process. Preliminary mechanistic investigations revealed that the transformation probably proceeded through a free radical pathway.