The usual copy/paste to CorelDraw and export_fig do not save transparency in patches. Instead, print to pdf and import the pdf:

Option 1

>>print(gcf, '-dpdf', 'D:\temp\sao2.eps');

Import (drag) "sao2.eps") in CorelDraw, and all is good.

Option 2

Export figure to "svg" format with plot2svg from File Exchange*
- CSPM includes this under ...\CSPM\plot2svg

>> addpath c:\matlab\spm12\toolbox\CSPM\plot2svg

- Click on figure (to make it "current figure")
- Save as SVG file in MATLAB's current folder

>> plot2svg('filename.svg')

* MATLAB 20016a: need to fix bug in plot2svg

Copying and pasting does not work.