TLDR: No, there is not inbuilt functionality to convert R code to MATLAB code
No, MATLAB and R are essentially two different programming languages and there does not exist any inbuilt utility in either MATLAB or R to convert the Coder from one to another.
There might exist any external utility or hard coded converter that does the job, one such utility can be found here which can be given a try https://www.mathworks.com/matlabcentral/fileexchange/5051-matlab-r-link
Note-: There exist inbuilt MATLAB products that can convert MATLAB code to C/C++ or static and dynamic libraries and executables. Search for MATLAB Coder or the 'codegen' command.
