NEWS OF TH E WEEK
TIANHE SHARES PLUNGE AFTER TRADING RESUMES
Tianhe has repeatedly denied the allegations and even posted a 55-page document on its website, on Oct. 8, in rebuttal. In an open letter to investors that day, Wei Xuan, Tianhe’s CEO and largest shareholder, said Anonymous Analytics is making “malicious and blatantly wrong allegations” in an effort to profit from its “downward manipulation” of Tianhe’s stock. The firm says Anonymous Analytics does not understand the antimar market. Anonymous Analytics claims it is not betting against Tianhe’s shares, but it acknowledges that people and organizations it interacts with may be doing so. Tianhe’s shares did bounce back by about 10% on Oct. 10, the day after their plunge, when the company says Wei bought $13.6 million worth of stock. But on Monday, Oct. 13, the shares resumed their slide. The stock steadied only on Oct. 15 when Tianhe announced it would buy back up to $150 million of its own shares, representing about 3.25% of its issued share capital. Tianhe is backed by the investment bank Morgan Stanley, which, through an affiliate, invested $300 million in the company prior to its initial public offering of stock in June. Anonymous Analytics is one of several groups that in recent years have denounced as frauds Chinese firms listed abroad (C&EN, Oct. 13, page 17). In most cases, the Chinese companies’ stock either collapsed or was hit with a trading suspension.—JEAN-FRANÇOIS TREMBLAY
FINANCE: Investors dump stock of Chinese chemical firm accused of fraud
T
HE MARKET VALUE OF Tianhe Chemicals—ac-
cused of fraud by a shadowy group affiliated with the hackers known as Anonymous—plummeted 40% after its shares resumed trading on Oct 9. Tianhe and the group, Anonymous Analytics, have exchanged a volley of charges and countercharges. In September, the Stock Exchange of Hong Kong had suspended trading of Tianhe Chemicals stock after Anonymous Analytics, in a 65-page report, accused the firm of being “one of the largest market frauds ever conceived.” The group accuses Tianhe of falsifying sales and profit figures; inventing its main customers; not possessing the technology for making its most profitable product, a touchscreen fluorochemical treatment known as anti-mar; and falsifying tax documents to prove its net income. NEWSCOM
Traders on the floor of the Hong Kong Stock Exchange bear witness to a dive in the value of Tianhe stock.
HOST TO THE UNEXPECTED ORGANIC CHEMISTRY: Nanovessel
catalyzes SN2 reaction with a surprising stereochemical outcome
A
CHANGE TO THE CANON of organic chem-
istry appears to be in order. Chemists at the University of California, Berkeley, report an SN2 reaction that proceeds with retention of stereochemical configuration (J. Am. Chem. Soc. 2014, DOI: 10.1021/ ja508799p). The reaction takes place within an organogallium host. Students of organic chemistry learn early on that SN2 reactions are characterized by inversion of stereochemical configuration. The incoming nucleophile displaces the leaving group on a carbon atom through a so-called backside attack that flips the arrangement of the carbon’s three other substituents. It’s akin to an umbrella becoming inverted by a strong gust of wind. Chen Zhao, F. Dean Toste, Kenneth N. Raymond, and Robert G. Bergman discovered they could make the reaction proceed with CEN.ACS.ORG
8
J. AM. C HEM. SOC.
This organogallium nanovessel catalyzes an apparent SN2 reaction proceeding with stereochemical retention (C,H = white, O = red, N = blue, Ga not visible).
stereochemical retention quite by accident. They’d come across a clever way of making single diastereomers of so-called nanovessel hosts and hoped to use them in asymmetric reactions. But when they tried to use the nanovessel for a substitution reaction on a racemic mixture of a benzylic substrate with the hope of getting primarily one enantiomer of product, their results were disappointing. So, they looked at what happened when they did the same reaction on a single enantiomer of the benzylic substrate. Much to their surprise, the reaction proceeded with up to 90% retention of stereochemical configuration. “We think that what we’re seeing is a kind of double inversion,” Bergman explains. As the leaving group departs, the π-electrons from one of the naphthalene groups that make up the nanovessel’s walls interact with the backside of the developing carbocation in the benzylic substrate. This sort of interaction has been observed before with neighboring groups within a substrate molecule but never intermolecularly. “This paper is a great combination of good, oldfashioned sleuthing applied to the frontiers area of supramolecular host-guest catalysis,” comments Ryan A. Shenvi, an organic chemist at Scripps Research Institute, in La Jolla, Calif., who has also tinkered with the canon of SN2 reactions. “It’s easy to imagine many more discoveries snowballing from this single observation,” he says.—BETHANY HALFORD
OCTOBER 20, 2014
