Studies towards the Total Synthesis of Drimentine C. Preparation of the AB and CDEF Ring Fragments

Abstract

The drimentine family is a class of hybrid isoprenoids derived from actinomycete bacteria. Members of this family display weak antitumor and antibacterial activity. Herein we report our efforts toward the total synthesis of drimentine C using three distinct approaches incorporating palladium-catalyzed Figure 1. General scaffold of drimentines and structure of indotertine A.[a] Scheme 2. Synthesis of terpenoid fragment 9 and attempts at organolithium coupling.

Decarboxylative Halogenation of Organic Compounds

“… Additionally, prefunctionalization of the acid with an alkyl chloroformate and CDI proved to be useful . Other successful esterification techniques include the use of pyrithione derivatives, such as 305 , ,− 306 , and disulfide dipyrithione 307 (in combination with tributylphosphine) . The purity of reagent 305 was found to have a profound effect on the reaction yield …”

MHAT-initiated redox radical cyclization of alkenylsilane enables concise syntheses of (–)-habiterpenol and (+)-2,3-epi-habiterpenol

“…habiterpenol analogs for a structure-activity relationship (SAR) study 8 . To further improve the synthetic method, we developed a concise route with the key reactions being the coupling of achiral indene 6 (DE-ring unit), which could be easily derived by a few steps, and aldehyde 7 (AB-ring unit) 9 and construction of the C ring through radical cyclization initiated by metal hydride hydrogen atom transfer (MHAT) 10 . Indene 6, which has a bulky and easily removable TMS group, was used to improve the st ereoselectivity of the coupling reaction with aldehyde 7 to construct the C3 quaternary stereocenter.…”

Diketopiperazine Gels: New Horizons from the Self-Assembly of Cyclic Dipeptides

“…The C-C disconnection ( Scheme 1 , C) often involves enolate acylation, albeit radical routes were also described to attain the C-C cyclization [ 63 ]. Despite the various synthetic routes available, the search is still active in this area with new developments pertaining to CDP synthesis appearing also in the most recent literature [ 68 , 69 , 70 , 71 , 72 , 73 , 74 , 75 , 76 ].…”