Catalyst‐controlled regiodivergent catalysis is a vital chemical tool that allows efficient access to large collections of structurally diverse molecules from a common precursor but remains a challenge. We report a catalyst‐controlled, tunable, and predictable regiodivergency in transforming the internal aliphatic propargyl esters into diverse libraries of highly substituted 1,3‐dienyl and allyl products by Pd‐catalysis. Depending on the ligand employed, the palladium catalyst can involve two typical approaches: electrophilic palladium catalysis and a sequential oxidative addition–reductive elimination pathway. This regiodivergent protocol endows facile access to four regioisomers with high regio‐ and stereoselectivity from the common propargyl esters. In terms of synthetic utility, a notable feature of this protocol is amenable to structural diversification of bioactive relevant molecules, enabling rapid assembly of many useful structural analogs of pharmaceutical candidates.

Catalyst-controlled regiodivergent catalysis is a vital chemical tool that allows efficient access to large collections of structurally diverse molecules from a common precursor but remains a challenge. We report a catalyst-controlled, tunable, and predictable regiodivergency in transforming the internal aliphatic propargyl esters into diverse libraries of highly substituted 1,3dienyl and allyl products by Pd-catalysis. Depending on the ligand employed, the palladium catalyst can involve two typical approaches: electrophilic palladium catalysis and a sequential oxidative addition-reductive elimination pathway. This regiodivergent protocol endows facile access to four regioisomers with high regio-and stereoselectivity from the common propargyl esters. In terms of synthetic utility, a notable feature of this protocol is amenable to structural diversification of bioactive relevant molecules, enabling rapid assembly of many useful structural analogs of pharmaceutical candidates.

Gelatinized starch paste was prepared by gelatinizing rice starch at 95°C in a water bath. Then, the rice starch (both normal rice starch and waxy rice starch) paste was subjected to high-pressure homogenization at homogenizing pressure of 20, 40, 60, 80 MPa. The rheological properties (including shear stress versus shear rate, apparent viscosity versus shear rate and thixotropy) of starch paste were studied. The high-pressure homogenization was able to improve the flow properties of starch paste. The shear stress increased with the increasing shear rate, and the Power law equation was capable of fitting the shear stress versus shear rate quite precisely. High-pressure homogenization treatment sharply decreased the thixotropy of starch paste, and the thixotropy of rice starch (both NRS and WRS) paste decreased with the increasing homogenous pressure. Efectos de la homogeneización a alta presión sobre las propiedades reológicas del almidón de arroz RESUMEN Para el presente estudio se preparó pasta de almidón gelatinizada, gelatinizando almidón de arroz a 95ºC en un baño de agua. Luego, la pasta de almidón de arroz (tanto de almidón de arroz normal (NRS) como de almidón de arroz ceroso (WRS)) fue sometida a homogeneización a alta presión, utilizando una presión de homogeneización de 20, 40, 60, 80 MPa. Posteriormente, se estudiaron sus propiedades reológicas (incluida la tensión de corte versus la velocidad de corte, la viscosidad aparente versus la velocidad de corte y la tixotropía). La homogeneización a alta presión mejoró las propiedades de flujo de la pasta de almidón. El esfuerzo cortante aumentó con el incremento de la velocidad de corte, y la ecuación de la ley de potencia fue capaz de ajustar la tensión de corte versus la velocidad de corte con bastante precisión. El tratamiento con homogeneización a alta presión disminuyó drásticamente la tixotropía de la pasta de almidón; además, la tixotropía de la pasta de almidón de arroz (tanto NRS como WRS) disminuyó con el aumento de la presión homogénea.

We report the first catalyst-controlled regiodivergent method that enables the synthesis of structurally diverse 1,2,3,4-tetrasubstituted conjugated dienes with excellent regio-and stereochemical outcomes from the same set of readily available propargyl esters and diaryliodonium salts. In this diene chemistry, the in situ generated, highly electrophilic aryl−Cu III complex serves not only as a π-Lewis acid catalyst for alkyne activation/acyloxy migration but also as an aryl electrophile equivalent. The competitive arylative 1,2-and 1,3-acyloxy migration patterns are exquisitely dictated by Cu and Au/Cu relay catalyses, respectively, providing a modular and attractive approach to traditionally inaccessible tetrasubstituted 1,3-dienes in a regiodivergent manner. Finally, the synthetic utility of this method is demonstrated by further synthetic derivatization of 1,3-dienes into an array of useful compounds.