This doesn't involve any loop, either explicit or via any of the ***fun functions. However all the structures in the map must have identical fields and all the structures must be scalar:
allvalues = yourmap.values; %extract values, stored as a cell arrays
allvalues = vertcat(allvalues{:}); %convert cell array of N structures into a Nx1 structure array, will fail if at least one structure has different fields
fieldvalues = vertcat(allvalues.My_Filed); %extract field into a Nxm matrix. Will fail if at least one field is not the same size as the others
