Citizen chemists: let's imagine each wants 100+ different reactants, and not every citizen chemist wants the same ones, then your offer must exceed 1000 reactants right from the beginning. This looks (to me!) like an excessive effort for a start-up.
Again my gut feeling: selling reactants to citizen chemists must be a strictly commercial activity, not one of development and production. Buy the 1000 different reactants in 100kg amount on alibaba, store, sell them in 100g amount.
Horrifying prices at Aldrich, Merck and the others: sure, and this can spark off vocations. But isn't their huge catalogue a must? If you need 10 compounds for your next lab trial, of which 1 or 2 are cheaper at newcheapercompany.com but the 8 others are available only from Aldrich, and you know it will be the same next time, will you really issue a separate order for the 1 or 2 compounds?
My similar experience here is more from electrical engineering, and I did just like my colleagues: I bought from the big supplier only because he had everything. Worse: I designed my circuits around the components available from him.
So the entry ticket to compete against Aldrich might be: design production methods for >1,000 compounds first, begin to sell only then. Huge investment.
With "silicon containing reactants", I meant reactants specific to one known synthesis reaction. If you pick a recent reaction, the offer by the established companies may still be limited, so you could show a broader catalogue with a reasonable effort.
Many people here could tell it better. For what reactions are the catalogues of reactants too narrow?
I feel important that your company's offer is very clear to the customers' mind, especially if you're not a giant. If you're "the company that sells more varied reactants for the xyz reaction", or NMR solvents, or deuterated compounds, or ultra-anhydrous compounds... then potential customers will think to you when they have this need. But if you're a small competitor to Aldrich, they'll forget you. And the clearer your catalogue is to categorize mentally, the better you'll stay in customers' mind.
Fragrances: aren't many companies already doing that?
The story with the branched alkanes is just that as I thought at rocket fuels for Mars and the Moon, many other potential uses popped up, some of which accept expensive compounds, so I got the impression that there is an opportunity for a start-up here.