Expression to construct a anonymous record with named columns?

Hello,

Is there a way to construct write an expression that constructs a record
with with named columns. Specificially without the need for a
corresponding named type.

That is

postgres=# select row(1, 2, 3);
row
---------
(1,2,3)
(1 row)

Creates a unnamed record type. And indeed it is for example not possible
to expand it:

postgres=# select (row(1, 2, 3)).*;
ERROR: record type has not been registered

On the other hand columns listed in a multi column select clause create a
row type that is expandable and named:
postgres=# select ((bar.*).x).a from (select x from (select 1 as a, 2 as b)
x) bar;
a
---
1
(1 row)

But it seems to not be possible to do so without a from clause:

postgres=# select ((select x from (select 1 as a, 2 as b) x)).a;
ERROR: syntax error at or near "."
LINE 1: select ((select x from (select 1 as a, 2 as b) x)).a;
^
postgres=# select ((select x from (select 1 as a, 2 as b) x)).*;
ERROR: syntax error at or near "."
LINE 1: select ((select x from (select 1 as a, 2 as b) x)).*;

So named anonymous records / row types seem to be strangely second class.
Can somebody clarify the restrictions and rationale or even better show a
way to do the equivalent of (made up syntax ahead):

select row(1 as a, 2 as b);

Cheers,

Bene