I tried to keep the trades realistic and based on rumors (when I could)
BOS - Pekovic (expiring), D. Williams
LAL - Garnett, Barea
MIN - Gasol
BOS - Jackson (expiring), Leonard, Bonner
SAS - Pierce
BOS - L. Williams, Korver (expiring), Morrow (expiring), Petro (expiring), Jenkins, 2013 Rockets 1st (lotto prot), 2014 ATL 1st
ATL - Rondo, Terry, Bass
BOS - Speights
CLE - Granger
IND - Green, Melo, 2013 Miami 1st (from CLE), 2013 ORL 2nd (from CLE)
BOS - Allen (expiring)
MEM - Lee
Boston totally wipes out it long term salaries, collects 2 more upcoming 1sts, and quite a few young assets such as Pekovic, L. Williams, Leonard and gets extended looks at Speights, Jenkins, and D. Williams all while keeping Bradley and Sullinger. Clearly Boston will be terrible the rest of the year, but this trade is about building assets, utilizing the draft, and opening up cap space this summer. In fact these trades will likely allow Boston to sign 2 max players (or certainly awful close to 2 max) and still potentially re-sign Pekovic (as long as he doesn't want max type dollars).
Obviously risky, but at the same time could certainly work out in the end for Boston.