An Efficient Enantioselective Synthesis of (2R)-Hydroxymethyl Glutamic Acid and an Approach to the (2R)-Hydroxymethyl-Substituted Sphingofungins
摘要:
We have developed a short enantioselective synthesis of (2R)-hydroxymethyl glutamic acid (HMG) starting from Garner's aldehyde using an alkylidene carbene 1,5-CH insertion as a method to construct the quaternary stereocenter. A variety of conditions were examined for the oxidative cleavage of the key cyclopentene intermediate and we found that RuCl3/NaIO4 led directly to the desired amino bis-acid product. We were also able to show that oxidative cleavage of the cyclopentene 1,5-CH insertion product could be used to produce the amino acid-containing skeleton of the sphingofungin family of natural products.
Construction of Quaternary Carbon Stereocenter of α-Tertiary Amine through Remote C–H Functionalization of Tris Derivatives: Enantioselective Total Synthesis of Myriocin
for the construction of the quaternary carbon stereocenter of α-tertiary amines. This strategy highlights a site-selective C–H functionalization involving an alkoxy-radical-triggered 1,5-hydrogen transfer (1,5-HAT) reaction of a conformationally fixed spiro-compound derived from trishydroxymethylaminomethane (Tris). The utilization of this strategy enabled an enantioselectivetotalsynthesis of myriocin