"Hydrogen is a light, odorless gas, which, given enough time, turns into people."
- Edward R. Harrison, 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"
"...there are things that are not absolutely correct with a capital 'C', but extremely worthwhile because they're major assumptions which allow things to move forward."
- Gilbert Stork, Chemical Heritage Foundation Oral History
"'Perfect' means you get to a point where there's nowhere left to go."
- Natasha Vita-More, SYFY25 Origin Stories podcast
"Our goal is not truth, a philosophical term, but rather a consistent description and interpretation of phenomena within a model concept."
- Rof Huisgen, The Adventure Playground of Mechanisms and Novel Reactions
"The only criterion of a model is its usefulness, not its 'truth'."
- Michael Dewar, J. Am. Chem. Soc. 1984, 106, 669
"...the search for fact, not truth"
- Dr. Henry Jones, Jr., "Indiana Jones and the Last Crusade"
"Chemistry needs models but chemistry also needs to recognize that models are models."
- Timothy Clark and Martin G. Hicks, "Models of Necessity"
Fellow, American Chemical Society (ACSF), 2017
Fellow, Royal Society of Chemistry (FRSC), 2016
Fellow, American Association for the Advancement of Science (AAAS), 2016
Associate Professor, UC
Assistant Professor, UC
Postdoctoral Associate, Cornell
AB, Chemistry, Harvard
(1973) and raised in Quincy,
Google Scholar Profile
American Scientist Profile
Chemical Family Tree
@TantilloLab on Twitter
on career path
on why I like being a professor
on drawing structures and air hockey
The Tantillo group is committed to cultivating an inclusive laboratory by respecting and engaging all members, providing equitable access to opportunities and resources, and embracing new perspectives and ideas. We believe that diversity in knowledge, life experiences, self-expression, and identity furthers chemistry knowledge and enriches the chemistry community. We value the uniqueness of each member, because our differences are our greatest strength.
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.
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.
methods, we like to make structural and reactivity predictions and have these predictions put to the test in the wet lab.
Reactivity/selectivity models and methods we have helped develop:
• extreme asynchrony in circumventing orbital symmetry constraints (Tetrahedron 2008, 64, 5672)
• transition state complexation (e.g., J. Am. Chem. Soc. 2007, 129, 8686)
• 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)
portable models of entropy
• a PES perspective: width, not just height, of pathways to products matters (e.g., Chem. Sci. 2020, 11, 9937)
• a non-covalent interaction perspective: electrostatic drag (e.g., Phys. Chem. Chem. Phys. 2020, 22, 26955)
selective synthetic reactions
• post-transition state bifurcations as sources of side products (e.g., Chem. Sci. 2017, 8, 1442)
• modulating selectivity for reactions with post-transition state bifurcations using non-covalent interactions (e.g., J. Am. Chem. Soc. 2017, 139, 7485)
• catalyst dissociation before catalytic cycle closure (e.g., J. Am. Chem. Soc. 2016, 138, 487)
natural products biosynthesis
• dominance of inherent substrate reactivity in some enzymatic reactions (e.g., Angew. Chem. Int. Ed. 2017, 56, 10040)
• post-transition state bifurcations as selectivity control elements in natural product biosynthesis (e.g., Nature Chem. 2014, 6, 104)
• dyotropic and triple-shift reactions increase the efficiency of terpene formation in Nature (e.g., J. Org. Chem. 2018, 83, 3780)
• secondary carbocations are rarely minima (e.g., Chem. Soc. Rev. 2010, 39, 2847)
• TerDockin, a tool for docking carbocations into terpene synthases (e.g., ACS Catal. 2018, 8, 3322)
• theory as an inspiration for natural product total synthesis (e.g., J. Am. Chem. Soc. 2012, 134, 18550 → Angew. Chem. Int. Ed. 2019, 58, 9851)
CheShiReCCat Chemical Shift/Coupling Constant Scaling Factor Website
Theoretical Physical Organic Chemistry (TPOC) Meetings ('21ff)
R Bryan Miller Symposium
Accelerating Reaction Discovery TSRC
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)
Department of Chemistry
UCD Chemical Biology Program (CBP)
ACS Organic Division
ACS Chemists with Disabilities
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
more details, follow the links below.
Teaching Experience and Awards
Databank of Dynamics Trajectories (DDT)
Taiwan Quarter Abroad Program
Pharmaceutical Chemistry Undergraduate Program
Making Computational Chemistry Accessible to Blind Students
Group in Action
Earned by Group Members
of the Labs
The Hottest Group Around
One of Dean's hobbies
science, and life
books and physical organic history
models and modelers
Videos (and more)!
Beyond chemistry - interested in virtual volunteering?
Dean with any questions, comments, or suggestions...