Herein we describe a phosphine-catalyzed internal redox [4 + 2] annulation of 1,4-enynoates with electron-deficient alkenes, in which the γand φ-C(sp 3 )−H of the enynoates are formally oxidized for the annulation while the alkynyl moiety is converted to an alkene. The reaction offers an efficient synthesis of highly functionalized cyclohexenes in moderate to good yields with exclusive regioselectivity and high diastereoselectivity under mild conditions.

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A flexible approach to the beta-hydroxy gamma-amino acid residue (fragment C) of hapalosin has been developed on the basis of the the regio- and diastereoselective Grignard reaction. The method allows the introduction of different side chains at the C9 of hapalosin. Asymmetric syntheses of hapalosin (1a), 9-homohapalosin (1b), 9-i-butyl-hapalosin (1c), 8-epi-hapalosin (epi-1a), and three small libraries diversified at C9 (3-member, 1L3), C9/ C4 (9-member, 1L9), or C9/C4/C3 (27-member, 1L27) have been produced using this method.

Phosphoranyl radicals are essential mediators to bring about new radicals but often produce a stoichiometric amount of phosphine oxide/sulfide waste. Herein, we devised a phosphorus-containing species as a radical precursor, but without the generation of phosphorus waste. Accordingly, a catalyst-free synthesis of phosphinic amides from hydroxyl amines and chlorophosphines via P­(III) to P­(V) rearrangement is described. Mechanistically, it may involve the initial formation of a R2N–O–PR2 species that undergoes homolysis of N–O bonds and subsequent radical recombination.

The effect of Maillard reaction browning factors on the color enhancement of membrane clarification non-centrifugal cane sugar (M-NCS) in storage was explored. During storage, the color of M-NCS gradually browned and blackened. pH, the contents of glucose, fructose, protein, total amino acids and 5-hydroxymethylfurfural (5-HMF) decreased significantly. Meanwhile, the moisture content, relative percentages of volatile Maillard reaction products (MRPs) and the content of 3-deoxyglucosone (3-DG) increased during storage. The sucrose content remained stable. Correlation analysis shows all browning factors were significantly correlated with color. Multivariate data analysis results demonstrated that the compound effects of volatile MRPs, 3-DG, pH, glucose and total amino acids led to the color change of stored M-NCS. The order of effect on the color change of stored M-NCS was volatile MRPs > 3-DG > pH > glucose > total amino acids.