Stereocontrolled Synthesis of 2,4-Diamino-3-hydroxyacids Starting from Diketopiperazines: A New Route for the Preparation of Statine Analogues

alpha-Amino-beta-hydroxy-gamma-lactam for constraining peptide Ser and Thr residue conformation

Alpha-amino-beta-hydroxy-gamma-lactam 1 is a peptide mimic in which the Ser/Thr residue omega-, psi-, and chi-dihedral angle geometry all are constrained by the 5-membered lactam ring. Lactams 1 were made by employing N-(Fmoc)oxiranylglycine 3 as a bis-electrophile in TFE with cat. BzOH to sequentially alkylate and acylate a variety of amino acid derivatives in one pot. Solid-phase synthesis of beta-hydroxy-gamma-lactam 8, an analogue of the IL-1 modulator 101.10, was achieved using this method for studying Ser/Thr geometry.

A convergent route for the total synthesis of malyngamides O, P, Q, and R

A convergent, enantioselective and general synthetic route to a class of marine natural products-malyngamides O (1), P (2), Q (3), R (4), 5''-epi-3 and 5''-epi-4-bearing a novel vinyl chloride structural motif was developed. The key steps involved construction of the vinyl chloride functionality by Wittig reaction, a DCC/HOBt-promoted amidation, an aldol reaction in the construction of the basic backbone of 1, 2, 3, 4, 5''-epi-3, and 5''-epi-4, and methylation of an enol moiety via either base/acid conditions or a Mitsunobu reaction. Moreover, the absolute configuration of the stereogenic center at C-5'' in 3 was further confirmed by synthesis of the natural product and its C-5'' epimer.