(1) Go to this web site: http://www.ww2.dk/
(2) Click on "Luftwaffe Officer Career Summaries" in the Contents column along the left side of the page. This will open to a .pdf document that is divided into 4 sections based on the letters of the alphabet.
(3) Click on and open section A-F. It will take 5 seconds or so to open because it is 400 pages long.
(4) In the SEARCH block on the right side of the toolbar enter: Staka 2./JG 27 and then hit Enter on your keyboard.
(5) This will give you the first name in A-F. For the next name in A-F (if any), click on the second of the two little icons just to the right of the SEARCH block. The first icon says "previous" and the second one says "next".
(6) Once you have finished with A-F, go to the next section (G-K) and repeat the process.
(7) You will have to do this with each Staffel (2., 6., 7.) and each section (A-F, G-K, L-R, S-Z), but in a few minutes you will have all of the Staffelkapitäne.
**Note: your initial question (Does anyone know the Staffel commanders of the 2 /6/7 staffel of II Gruppe Jadggeschwader 27 from 1941 through 1943?
) is wildly incorrect. The 2. Staffel did not belong to II. Gruppe and never did. It belonged to I. Gruppe. Only 6. Staffel always belonged to II. Gruppe. The 7. Staffel did not belong to II. Gruppe until late July 1944. Before that it belonged to III. Gruppe.
May I ask why you need these names? It is usually only those who have studied the Luftwaffe for many years who want this sort of rather finite detail.