Directed Orthometalation and the Asymmetric Total Synthesis of N-Deoxymilitarinone A and Torrubiellone B
摘要:
A diverted total synthesis (DTS) approach to the total synthesis of pyridone alkaloids N-deoxymilitarinone A (8) and torrubiellone B (10) has been developed. The common intermediate 14 was first assembled by a dual directed orthometalation process using a methoxymethyl group as directed metalation group. Other crucial steps include the assembly of polyenes under aldol condensation for DTS using general and concise strategy and diastereoselective synthesis of the syn-dimethyl array by an Evans aldol reaction.
Directed Orthometalation and the Asymmetric Total Synthesis of N-Deoxymilitarinone A and Torrubiellone B
摘要:
A diverted total synthesis (DTS) approach to the total synthesis of pyridone alkaloids N-deoxymilitarinone A (8) and torrubiellone B (10) has been developed. The common intermediate 14 was first assembled by a dual directed orthometalation process using a methoxymethyl group as directed metalation group. Other crucial steps include the assembly of polyenes under aldol condensation for DTS using general and concise strategy and diastereoselective synthesis of the syn-dimethyl array by an Evans aldol reaction.
Four stereoisomers of the spider-pathogenic fungus metabolite torrubiellone D were synthesized for the first time in 10% overall yield starting from l-tyrosine or d-tyrosine. The 3-decatrienoyl side chain was assembled and attached via (E)-selective HWE and Wittig olefinations. Their antibiotic activities against drug-susceptible Escherichia coli strains differed considerably.