"Hydrogen... a light, colorless, odorless gas, which, given enough time, turns into people."

- Ted Harrison, British Astronomer/Cosmologist

"For first the first-beginnings of things move of themselves; then those bodies which are formed of a tiny union, and are, as it were, nearest to the powers of the first-beginnings, are smitten and stirred by their unseen blows, and they in their turn, rouse up bodies a little larger. And so the movement passes upwards from the first-beginnings, and little by little comes forth to our senses, so that those bodies move too, which we can descry in the sun’s light."

- Titus Lucretius Carus, "On the Nature of Things"

"'Perfect' means you get to a point where there's nowhere left to go."

- Natasha Vita-More, SYFY25 Origin Stories podcast

"...the search for fact, not truth"

- Dr. Henry Jones, Jr., "Indiana Jones and the Last Crusade"



Fellow, American Chemical Society (ACSF), 2017

Fellow, Royal Society of Chemistry (FRSC), 2016

Fellow, American Association for the Advancement of Science (AAAS), 2016

Professor, UC Davis, 2011-present

Associate Professor, UC Davis, 2008-2011

Assistant Professor, UC Davis, 2003-2008

Postdoctoral Associate, Cornell University, 2000-2003

with Roald Hoffmann

PhD, Chemistry, UCLA, 1995-2000

with Ken Houk

AB, Chemistry, Harvard University, 1991-1995

Born (1973) and raised in Quincy, Massachusetts, USA


Brief CV

Google Scholar Profile

SCOPUS Profile

Chem-Station Profile

ORCID Profile

Chemical Family Tree

Ramblings on Career Path

American Scientist Profile

Why I Like Being a Professor


Our research is driven by intriguing mechanistic and structural questions and spans many areas of organic chemistry. These include natural products synthesis and biosynthesis, enzyme catalyzed reactions, polycyclization reactions, catalyst design, physical organometallic chemistry, carbocation structures and rearrangements, pericyclic reactions, regio- and stereoselectivity of synthetically useful reactions, and computer-aided design of enzyme inhibitors and unusual substrates.

Our group is particularly intrigued by the mechanisms of carbocation cyclization/rearrangements used by Nature to synthesize complex terpene natural products such as those shown below.

Our primary tool for tackling mechanistic problems is quantum chemistry. We apply various methods - e.g., density functional theory (DFT) - to compute structures, relative energies, activation barriers, potential energy surface (PES) shapes, NMR/IR/UV/VCD spectra, isotope effects, and solvation effects. We also make use of ab initio direct dynamics trajectory calculations to explore nonstatistical dynamic effects on reactivity.

Using these methods, we like to make structural and reactivity predictions and have these predictions put to the test in the wet lab.

Reactivity/selectivity models we have helped develop:

width, not just height, of pathways to products on PESs matters (e.g., J. Am. Chem. Soc. 2017, 139, 7485)

electrostatic drag (e.g., J. Am. Chem. Soc. 2017, 139, 7485)

dominance of inherent substrate reactivity in some enzymatic reactions (e.g., Angew. Chem. Int. Ed. 2017, 56, 10040)

post-transition state bifurcations as sources of side products (e.g., Chem. Sci. 2017, 8, 1442)

sulfur-lone pair interactions are not necessarily dominated by lone pair donation to S–X antibonding orbitals (e.g., Org. Biomol. Chem. 2017, 15, 3179)

catalyst dissociation before catalytic cycle closure (e.g., J. Am. Chem. Soc. 2016, 138, 487)

secondary carbocations are rarely minima (e.g., Chem. Soc. Rev. 2010, 39, 2847)

extreme asynchrony in circumventing orbital symmetry constraints (Tetrahedron 2008, 64, 5672)

transition state complexation (e.g., J. Am. Chem. Soc. 2007, 129, 8686)


Research Information

Research Projects


Cover Gallery


Grant Support

Computational Methods

CheShiReCCat Chemical Shift/Coupling Constant Scaling Factor Website


R Bryan Miller Symposium

Accelerating Reaction Discovery TSRC Workshop ('11ff)

West Coast Theoretical Chemistry Meeting ('20)

45th National Organic Symposium ('17)

Walking in the Woods with Chemistry at the UCD Arboretum ('16)

Reaction Mechanisms Conference ('14)

KurthFest ('13)

SYLICCO Conference ('07&'09)


Department of Chemistry

UCD Chemical Biology Program (CBP)

Accessible Science

ACS Organic Division

ACS Sacramento Section

Alliance for Diversity in Science and Engineering (UCD Chapter)

Agricultural and Environmental Chemistry Graduate Group



Dean has taught both graduate and undergraduate chemistry classes for both chemistry and non-chemistry audiences. These classes have ranged in size from less than ten to over three hundred students. For more details, follow the links below.


Dean's Teaching Experience and Awards

Dean's Teaching Philosophy

Taiwan Quarter Abroad Program

Pharmaceutical Chemistry Undergraduate Program

Making Computational Chemistry Accessible to Blind Students



Current Group Members

The Group in Action

Group Members Abroad

Group Alumni

Group News

Group Adventures

Awards Earned by Group Members

Group Data

Group Animals

Tour of the Labs

The Hottest Group Around


One of Dean's hobbies - flash fiction

Symmetry, science, and life

Representation and presentation

Old books and physical organic history

Organic models and modelers


Chemical wordplay

Logic and perspective

Beyond chemistry - interested in virtual volunteering?

Some acknowledgments


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Contact Dean with any questions, comments, or suggestions...