Chemoselective hydroxyl group transformation: an elusive target

Zn(OTf)2-promoted chemoselective esterification of hydroxyl group bearing carboxylic acids.

Selective esterification of aliphatic and aromatic carboxylic acids with various alcohols is studied using triphenylphosphine, I2, and a catalytic amount of Zn(OTf)2. Use of this catalyst allows the formation of esters at a faster rate with good to excellent yield by activating the in situ generated acyloxyphosphonium ion intermediate. During the esterification process, both their aromatic and ...

Software Quality: The Elusive Target

In the recent past, when bank statements contained errors or the telephone network broke down, the general public usually blamed "the computer," making no distinction between hardware and software. However, high-profile disasters and the ensuing debates in the press are alerting more people to the crucial nature of software quality in their everyday lives. Before long, we can expect increasing ...

Chasing an elusive target with a mobile robot

Studying an elusive cuckoo.

In a single nest, perched on a branch overhanging a marshy river in Panama, four birds jostle for space. The birds all belong to a species of cuckoo called the Greater Ani, and each one has offspring in the communal nest. The birds take turns warming the heap of eggs and looking out for predators, teaming together to face the challenges of rearing young. A dozen feet away, researchers peer out ...

Cohabitation : An Elusive Concept

Rates of out-of-wedlock births in the US have increased over the past three decades and rates of cohabitation among unwed parents have risen. Consequently, unwed parenthood is decreasingly synonymous with single parenthood. As we focus more attention on unwed parents, their living arrangements, and relationships, it is becoming clear that cohabitation is an ambiguous concept that is difficult t...