Bach arrangements are nothing new, but Thomas Oehler’s “reimagining” of three of the keyboard partitas opens up unexpected new soundworlds. Trevor Pinnock—more used to playing these works than conducting them—presides over an elite string ensemble, joined by flute, oboe, cor anglais, and bassoon. He encourages all their modern colors while insisting on historically sensitive phrasing and articulation, crisply clarifying Bach’s complex dialogue in the fugal “Gigue” of Partita No. 5. The players come into their own in the “Gigue” of Partita No. 1, where Oehler reinvents Bach’s finger-pleasing keyboard writing for the full ensemble, transporting us to the neoclassical style of the 20th century. The orchestral writing never tries to emulate Bach’s own; if anything, it’s the players’ instinct for Bach’s wit (such as in the “Praeambulum” to Partita No. 5) which has a hint of Stravinsky’s Pulcinella.