Stereodivergent Total Synthesis of (+)‐Aspergillide B and (+)‐7‐epi‐Aspergillide A

Abstract

The stereoselective total syntheses of (+)-aspergillide B and (+)-7-epi-aspergillide A were achieved. The key reactions include Noyori's asymmetric transfer hydrogenation, an Achmatowicz rearrangement, a Ferrier-type alkynylation, a 578 hydrosilylation-protodesilylation, a CBS (Corey-Bakshi-Shibata) oxazaborolidine reduction, a Yamaguchi macrolactonization, and a Mitsunobu macrolactonization.Scheme 2. Synthesis of acetate 7 (LDA = lithium diisopropylamide).

Stereodivergent Total Synthesis of Δ9‐Tetrahydrocannabinols

“…Consequently, this results in deviation from the primary synthetic sequence and thus different synthetic routes to the diastereomeric targets. [2] A largely unmet challenge, however, is the discovery and development of uniform synthetic strategies that provide controlled access to any given stereoisomer of a target. Herein, we report the implementation of such a strategy in the context of the total synthesis of the D 9 -tetrahydrocannabinols (1, all stereoisomers) that relies on an early stereodivergent step followed by a short uniform sequence ( Figure 1).…”

Applications of Mitsunobu Reaction in total synthesis of natural products

“…It also show cytotoxicity towards cancer cell lines including MDA‐MB‐231, HL‐60, and HT1080 cell lines . In 2012, Sridhar and Srihari achieved and reported a facile strategy for the stereoselective total synthesis of (+)‐7‐epi‐aspergillide A ( 238 ) (Scheme ) . In this strategy, the key reactions are Noyori's asymmetric transfer hydrogenation, Achmatowicz rearrangement, Ferrier‐type alkynylation, hydrosilylation–protodesilylation, CBS (Corey–Bakshi–Shibata) oxazaborolidine reduction and Yamaguchi macrolactonization as well as Mitsunobu macrolactonization.…”

“…[270] In 2012, Sridhar and Srihari achieved and reported a facile strategy for the stereoselective total synthesis of (+)-7-epi-aspergillide A (238) (Scheme 48). [271] In this strategy, the key reactions are Noyori's asymmetric transfer hydrogenation, Achmatowicz rearrangement, Ferrier-type alkynylation, hydrosilylation-protodesilylation, CBS (Corey-Bakshi-Shibata) oxazaborolidine reduction and Yamaguchi macrolactonization as well as Mitsunobu macrolactonization. The total synthesis of 238 started with providing the intermediate 241 as an appropriate precursor for Mitsunobu reaction from commercially available ethyl acetate (239).…”

Achmatowicz reaction and its application in the syntheses of bioactive molecules

“…223 In this case, the acid 188 could be derived from dihydropyranone, ent - 183 and trimethylsilylacetylene derivative 189 (Scheme 50). Acetal ent - 183 was obtained from the chiral furfuryl alcohol ( R )- 184 using an Achmatowicz reaction…”