Middle Holocene marine flooding and human response in the south Yangtze coastal plain, East China

Coastal flooding catastrophes have affected human societies on coastal plains around the world on several occasions in the past, and are threatening 21st century societies under global warming and sea-level rise. However, the role of coastal flooding in the interruption of the Neolithic Liangzhu culture in the lower Yangtze valley, East China coast has been long contested. In this study, we used a well-dated Neolithic site (the Yushan site) close to the present coastline to demonstrate a marine drowning event at the terminal stage of the Liangzhu culture and discuss its linkage to relative sea-level rise. We analysed sedimentology, chronology, organic elemental composition, diatoms and dinoflagellate cysts for several typical profiles at the Yushan site. The field and sedimentary data provided clear evidence of a palaeo-typhoon event that overwhelmed the Yushan site at ∼2560 BCE, which heralded a period of marine inundation and ecological deterioration at the site. We also infer an acceleration in sea-level rise at 2560–2440 BCE from the sedimentary records at Yushan, which explains the widespread signatures of coastal flooding across the south Yangtze coastal plain at that time. The timing of this mid-Holocene coastal flooding coincided with the sudden disappearance of the advanced and widespread Liangzhu culture along the lower Yangtze valley. We infer that extreme events and flooding accompanying accelerated sea-level rise were major causes of vulnerability for prehistoric coastal societies

Palladium-Catalyzed Domino Addition and Cyclization of Arylboronic Acids with 3‑Hydroxyprop-1-yn-1-yl Phosphonates Leading to 1,2-Oxaphospholenes

A novel and efficient palladium-catalyzed domino addition–cyclization of a wide range of arylboronic acids with various 3-hydroxyprop-1-yn-1-yl phosphonates has been developed, affording a convenient and powerful tool for the preparation of valuable 1,2-oxaphospholenes with mild reaction conditions, broad substrate applicability, and good to excellent yields. Mechanistic studies revealed that the reaction might involve Michael addition and nucleophilic substitution

DBSA-catalyzed hydrolysis of chain α-oxo ketene dithioacetals in water: Aqueous synthesis of β-ketothioesters

<p>In this paper, we wish to report an environment friendly synthetic method for β-ketothioesters from a dodecylbenzenesulfonic acid (DBSA)-catalyzed hydrolysis reaction of chain α-oxo ketene dithioacetals in water. It was shown that the hydrolysis reaction of chain α-oxo ketene dithioacetals could efficiently occur in the presence of 7.5 mol% DBSA at 100 °C in water, affording the desired β-keto thioesters in excellent yields.</p